Cold War British SPG Prototypes Has Own Video

Spartan 105 mm SPG

United Kingdom (1958)
Self-Propelled Gun – None Built

Spartan began as a design study at the Royal Military College of Science, Shrivenham for a Weapon and Fighting Vehicle Design involving the Officers on the group as well as members of the Technical Staff Course. The project was for the design of a close support artillery weapon that would be able to take part in the 1958 Tactical Battle in Nuclear War doctrine.

The UK was both at the forefront and also, paradoxically, a late bloomer in the Self Propelled Artillery (SPG) game, with the first platforms being the Mk.I Gun Carriers in World War 1. These were built as a result of the tank making its debut on the battlefield and the sudden realization that conventional horse-drawn artillery could be left lagging behind a more mobile army. The first of these was ready on March 3rd, 1917, participating in a Tank Trials Day. Fifty vehicles were ordered by the Army, to be produced by Kitson & Co. While the thought process was in the right area, they were still hindered by their ungainly design and never used in anger.

Various other systems were experimented with and, running alongside, the UK also built a series of vehicles called Dragons (a name taken from the simplification of ‘Drag Gun’) but these were no more than mechanical mules. What was needed was an all in one system, which was solved by the Birch Gun.

The Birch Gun, named after General Sir Noel Birch, who was Master General of Ordnance at the time, was a coupling of an 18 pdr gun (83.3 mm) with a Vickers Medium Mk.II chassis by the Royal Arsenal. This produced what could be argued as the first modern SPG, with a front-mounted engine, rotating gun turret, a crew that could travel with the weapon, and good cross country performance. Birch Guns were used in the Experimental Mechanized Force maneuvers of 1928 but by 1931 they had all been removed from service. This revolutionary design, which put the army decades ahead of its rivals, went the same way as anything that was new, innovative, or remotely useful to the army; precisely nowhere, as they chose not to use it. This inability or unwillingness to adapt or welcome new concepts would stymie the British Army until the present day where they still have the same issue.

By 1939, the UK realized it was inevitably going to be embroiled in another war with Germany and her allies. Hitler’s rise to power and the swift annexation of Czechoslovakia followed by the invasion of Poland led the UK to try and rapidly get the next generation of military vehicles into service as it was clear that mechanized mobility had been key to Germany’s success so far. Unfortunately, lessons learned with the Birch gun were not replicated and throughout most of the Second World War, the UK’s mobile self-propelled guns were lacking compared to both her opponents and her Allies.

Post-war, the UK began to reinvest in the concept of mobile artillery and, with new threats looming in the shape of Soviet Russia, new doctrines and tactics had to be accounted for in the design work. Several different vehicles and concepts were initialized. The FV304 and FV305 were to be built on the FV300 chassis armed with 25 pdr (88 mm) and 5.5 inch (139.7 mm) guns. Work stopped with only partial construction on the first and early layout work completed on the latter.

FV3802 and FV3805 were another two programs. FV 3802 was to be armed with the 25 pdr. while FV3805 was to have the 5.5 inch gun. Both were mounted on modified Centurion chassis in rear large casemates. Two prototypes were made (P1 and P2), although neither were accepted for service.


The introduction of tactical nuclear weapons (one must remember that, at this point in history, the consensus all round was that the next war would be nuclear without a doubt) left the army in need of new tactics based around mobility, counter-attack, and survival in an irradiated wasteland that would be the conflict zone. To avoid offering a nuclear strike target, the artillery had to be able to concentrate its effort by increased range, rate of fire, and lethality whilst having good mobility to remain dispersed and yet stay in contact. Protection also had to be altered. Open topped vehicles were unsuitable for this type of warfare and therefore protection had to be ensured to protect from flash burns, secondary blast effects as well as conventional threats.

The designers decided that heavy and conventional artillery would be required to break through the surviving enemy defenses, larger long-range field guns would be situated further back from where it’s believed tactical nuclear weapons would be used, and so they settled on the mobile medium range of SPG. Each vehicle would need to be amphibious without preparation (to prevent crew being irradiated), highly mobile with long endurance, and carry enough supplies to allow logistics trains to be reformed behind them.

Spartan was to be built of relatively thin welded steel armor stiffened with support braces with priority given to extra room for supplies and the large volume of ammunition that was expected. This increased internal volume also helped with buoyancy. In order to get the high arc of fire required to effectively ‘lob’ shells over ridgelines and areas in which enemy forces may be hiding, the gun was positioned as high above the vehicle floor as possible to allow for a lower breech drop. To achieve this, the gun cradle was to be suspended from two beams arched across the roof.

The fighting compartment housed a five-man detachment consisting of the commander, two loaders, gunner and driver, and 210 rounds of ammunition. Charges, fuses, and other requirements were kept in sponsons to either side. Large rear watertight doors to the back could be opened to assist in loading shells, which were gravity fed to assist the loader in battle. Other than being airtight with an overpressure system to prevent gas biological and nuclear agents from entering the vehicle, the armor itself* would stop harmful gamma rays while a plastic spall liner would protect against fast neutrons. All the optical devices had polarizing filters to prevent blindness from nuclear flash.

*While the original authors quote the armor would be adequate, correspondence between the author and a nuclear physicist confirmed suspicions that such material would offer no protection against the level of gamma radiation likely to be received.

Automotive power was provided by a turbo-blown, supercharged 400bhp Foden FD12 compression ignition engine which could run on fuels ranging from Diesel, Avtur, Kerosene, and MT 80. Sufficient fuel was carried to allow for a 24-hour operational day and the power and speed allowed it to keep up with other MBTs at an average combat speed of 15 mph (24 km/h). A Merritt Brown gearbox and disc brakes were fitted for the final transmission. The entire powerpack could be extracted via the rear doors on a pull-out roller sheet due to the gun and seat etc. being mounted from the ceiling.

The suspension was via 12 road wheels in 6 pairs on either side via hydraulically adjusted torsion bars allowing the vehicle to lower itself to the ground to provide a stable firing platform.


The gun was designed to replace the 25 pounder field gun and the 4.2 inch mortar in service. At a high angle, it was to engage targets between 1500 yards and 17,500 yards (1.4 km to 16 km) with a rate of fire of eight rounds a minute and new ammunition giving a marked performance upgrade over the 25 Pdr. The gun itself was a twelve-foot long (3.6 meter) monobloc non-autofrettaged barrel.

Autofrettage is a process by which the barrel is produced from a smaller caliber one by increasing the pressure on the inside of the barrel past its elastic limit. This enlarges the inner diameter of the barrel by pushing the inner layers of the barrel outwards, thus increasing the density as well. This gives a higher density barrel with better strength, lifetime, and safety. Made from a single forging of high-quality steel with a yield of 55 tons per square inch the gun was fitted with a fume extractor to assist with drawing fumes from the main compartment.

The gun was built to handle UK 105 mm HE and HESH bagged charges. However, an adaption existed to fit a replaceable liner and breach block that would allow it to use the US 155 mm rounds if required, this procedure taking about 2 hours. The new HE round was torpex based with a 60/30/10 mic fo RDX/TNT/AL mixture and an explosive filler of 6.6 lbs (3 kg) offering 250% more effective explosive volume over the older 25 pdr round. The horizontal sliding breech block was fitted with a semi-automatic gear for opening and closing the breach.

An automatic tube loading device with a tube magazine was incorporated for use when the British ammunition was fired. The ring-type cradle had parallel extension members at the rear to take anti-rotational slides for the block. The gun rammer was provided by compressed air in the engine compartment.

Sighting arrangements for the gun consisted of a conventional rocking bar sight and a long-necked dial sight. Laying for elevation was by means of a quadrant elevation bubble clinometer. A separate anti-tank periscope sight was mounted outside the cupola roof to avoid the effects of heat shimmer on the barrel.


The Spartan project certainly identified an area of light Self Propelled Artillery that was required for the MOD and the factors identified were already being used in several Russian developments despite there being no common communication between the developers. To add credence to this, a few years later, the F.V.433 Abbot began development which is remarkably similar in many ways to Spartan and may well have taken inspiration from the preceding project.

The Spartan had a very curious profile for a Self Propelled Gun. However, it was designed around the perceived needs of a war during which tactical nuclear weapons would be used. Illustration by Yuvnashva Sharma, funded by our Patreon campaign.


SPARTAN: Royal Military College of Science.
Discussions with Lucian Stan regarding radiation penetration


Dimensions 6.22 x 3.1 x 2.82 m (20ft5in x 10ft2in x 9ft3in)
Armament 105 mm Howitzer, with 210 rounds and 300 charges
Time to action 60 seconds
Crew 6
Propulsion Foden FD 12 multifuel 400 BHP at 2400 rpm
Speed 48 km/h (30 mph)
Range 645 km (400 mi)
Traverse Power assisted
Elevation From -5° to +75°
Gun Range 16 km (17,500 yards)
Total production None built
Cold War British SPG Prototypes Has Own Video

FV4005 – Heavy Anti-Tank, SP, No. 1 “Centaur”

United Kingdom (1950-1957)
Heavy Self-Propelled Anti-Tank Gun – 3 Built (1 Stage 1, 2 Stage 2)

In the late 1940s, the British War Office (WO) was concerned that – after the debut of the IS-3 in 1945 – the Soviet Union would continue to develop heavily armored tanks. As such, the War Office filed a requirement for the development of a gun capable of defeating a 60-degree sloped plate, 6 inches (152 mm) thick, at up to 2,000 yards (1,830 meters), and a suitable vehicle to carry it.

This requirement led to the development of the ‘Ordnance, Quick-Firing, 183 mm, Tank, L4 Gun’, the largest purpose-built anti-tank gun to have ever been created. It was intended that this gun would be mounted on a new ‘Heavy Gun Tank’ based on the FV200 series chassis. This was designated the ‘Tank, Heavy No. 2, 183 mm Gun, FV215’.

A project was also launched to find a way to get the gun into action quickly on an existing hull. This could then be constructed quickly should the Cold War turn hot before the FV215 was ready.

This is where the FV4005 project comes in.

The FV4005 Stage 2, also unofficially known as ‘Centaur’. The two visible crew members give an idea of the scale of the gun. Photo: The Dark Age of Tanks, David Lister. Colorized by Jaycee “Amazing Ace” Davis.

The Quest for Firepower

The development of the L4 started in 1950, and was aimed at increasing the firepower of the ‘Heavy Gun Tanks’. This was a uniquely British designation that was not governed by tank weight, but the size of the gun. A requirement was formulated for a tank armed with a gun capable of defeating a 60-degree sloped plate, 6 inches (152 mm) thick, at up to 2,000 yards (1,830 meters), a feat impossible even for the powerful 120 mm L1 gun of the FV214 Conqueror. By 1950, Major General Stuart B. Rawlins, Director General of Artillery (D.G. of A.) had concluded that there was no gun available with that level of ballistic performance and an investigation was launched. Initially, the British Military looked at the development of a 155 mm gun that would be standardized with the USA. However, even this lacked the required punch and, as such, 6.5 and 7.2 inch (165 and 183 mm respectively) High-Explosive Squash Head (HESH) shells were looked at.

At this time, the British Army came to the conclusion that a ‘kill’ did not necessarily mean the complete destruction of an enemy vehicle, and just damaging it was enough to take it out of action was enough. For example, a blown-off track is seen as a kill as it took the enemy vehicle out of action; today this is known as an ‘M’ (Mobility) kill. A ‘K’-Kill would be the destruction of a vehicle. The term used for this method at the time was ‘disruption not destruction’. The 6.5 in/165 mm HESH was not thought to be powerful enough to ‘kill’ a heavily armored target in this manner unless it hit bare armor plate. Attention, therefore, turned instead to the larger 7.2 in/183 mm shell which – Maj.Gen. Rawlins thought – would be powerful enough to render the target inoperable, and therefore ‘kill’ it, wherever it impacted.

The monstrous 183 mm L4 installed in the open-turret of the FV4005 ‘Stage 1’. The location appears to be ‘Workshop 5’ (the so-called ‘secret shed’ at Elswick) Photo: Ed Francis

The projected gun was designated the 180 mm ‘Lilywhite’. The background of this name is unknown. It may be an interpretation of the ‘Rainbow Code’ used by the WO to identify experimental projects. The ‘Red Cyclops’ flame gun attachment for the FV201, and the ‘Orange William’ experimental missile are examples of this. If this was the case, however, the name should be ‘White Lilly’. It may even simply be named after a Lieutenant Colonel Lilywhite of the Royal Army Ordnance Corps. It must be said that this is all speculation, and no evidence currently exists to support the theory.

It was not until December 1952 that the designation of the gun was officially updated to 183 mm. The design of the gun was accepted and was serialized as the ‘Ordnance, Quick-Firing, 183 mm, Tank, L4 Gun’. In reality, only the HESH shell underwent further development and the number of charges was dropped to one. The 183 mm L4 became one of the largest and most powerful tank guns in the world.

Background of the Project

From the start, the FV215 was the intended mount for the 183 mm gun, with development starting around the same time as the gun in 1950. The vehicle was based on the FV200 series chassis, with similarities to the FV214 Conqueror. The turret, however, was moved to the rear of the vehicle. The turret was capable of full 360-degree traverse, but it had a limited firing arc due to the size and power of the gun. This ‘Heavy Gun Tank’ would take a while to develop, so, in November 1950, the WO filed a requirement for a stop-gap vehicle capable of carrying the weapon into service should hostilities erupt before the completion of the FV215. A similar connection can be found with the Conqueror and the FV4004 Conway.

A developmental image of the ‘Tank, Heavy No. 2, 183 mm Gun, FV215’ – the intended carrier of the 183 mm L4 Gun. Photo: Rob Griffin, Conqueror

Following the end of General Rawlins’ investigation, and with some degree of urgency to get the 183 mm gun into service as quickly as possible, a carrier design was finalized, as this extract from a 1951 ‘AFV Development Report’ describes:

“A limited traverse, lightly armoured S.P. mounting based on the Centurion hull and weighing some 50 tons[*]. This would be known as F.V.4005 and could be in production by December 1952. Because of the use of parts in existing production, it was considered that quick limited production could be achieved. It was also clear that much would be learned about the hitherto unknown art of mounting so large a gun as an S.P. mounting.”

*50 long tons. Long tons are a unit of mass unique to the United Kingdom; for ease, it will be shortened to ton when used again. 1 long ton is equal to about 1.01 metric tonnes, or 1.12 US ‘Short’ tons.

The design of the vehicle would be held in limbo, ready to go into production if necessary. This stopgap vehicle would be based on the Centurion of the FV4000 series, with the original turret removed. The vehicle would go through two ‘Stages’ or ‘Schemes’. ‘Stage 1’ was built to test the gun and its mount on the Centurion chassis. The ‘Stage 2’ was a finalized design and would be the production standard. The vehicle was given the designation of ‘Heavy Anti-Tank, SP, No. 1’ – ‘SP’ standing for ‘Self-Propelled’. Officially, the FV4005 was never given the traditional British ‘C’ name such as the FV4101 Charioteer and FV4004 Conway before it. However, extensive account files of Vickers Ltd. from 1928 to 1959, shed some light on what it may have been. This particular extract – graciously provided by researcher Ed Francis – is from December 1952:

“Design and manufacture of equipment for mounting 180 mm gun on “CENTAUR” Tank – FV4005. Trials have now been carried out at Ridsdale and certain modifications to design have been found necessary… ”

In total three prototypes were ordered – a single Stage 1, and two Stage 2s. The FV4005 would fill the role of a ‘Heavy Gun Tank’. As such, the vehicle would engage targets from long-range, firing over the heads of attacking lighter tanks.

The Centurion Hull

The Centurion was chosen as the basis for this vehicle and three Mk.3 hulls were removed from service for the prototype development. Other than the removal of the turret and various small additions, the hull would remain mostly unaltered. Armor on the hull remained the same thickness, with about 3 inches (76 mm) at roughly 60 degrees on the front slope. A 650 hp Rolls-Royce Meteor petrol engine, located at the rear of the vehicle, propelled the tank. The Centurion used a Horstmann style suspension, with 3 bogies per side carrying 2 wheels each. The drive sprocket was at the rear with the idler at the front. The driver was located at the front right of the hull.

The Centurion Mk.3. The FV4005 prototypes were based on the hulls of Mk.3s. Photo: super-hobby

Details of the 183 mm L4

Just a small number of the ‘Ordnance, Quick-Firing, 183mm, Tank, L4 Gun’ were built, but it is unclear just how many. Records suggest at least 12 were built. Unfortunately, the exact length of the 183 mm gun is currently unknown, but it was somewhere in the region of 15 feet (4.5 meters) long. It was fully rifled with a large ‘bore-evacuator’ (fume extractor) placed roughly half-way down its length. The gun alone weighed 3.7 tons (3.75 tonnes).

High-Explosive Squash Head (HESH) was the only ammunition type to be produced for the 183 mm gun. Both the shell and the propellant case were of gargantuan proportions. The shell weighed in at 160 lbs. (72.5 kg) and measured 29 ¾ inches (76 cm) long. The propellant case weighed 73 lbs. (33 kg) and measured 26.85 inches (68 cm) long. The case contained a single charge that propelled the shell to a velocity of 2,350 fps (716 m/s). When fired, the gun produced 86 tons (87 tonnes) of recoil force and had a recoil length of 2 ¼ feet (69 cm).

Artist’s representation of the 183 mm HESH shell and its propellent case, in scale with a 6 foot (1.83 meter) man, based on recorded dimensions. The markings and colour of the shell are purely speculative but are based on British markings of the time. Image produced by Tank Encyclopedia’s Mr. C. Ryan.

HESH shells have an advantage over regular kinetic energy rounds as their effectiveness does not decrease with distance. This shell works by creating a shockwave on detonation. Once this wave reaches a void, it reflects back. The point at which the waves cross causes tension feedback which rips apart the plate, carrying a scab with approximately half the kinetic energy forwards, scattering shrapnel around the interior of the target. Test firing of the L4 against a Conqueror and a Centurion proved how powerful the round was. In two shots, the 183 mm HESH shell blew the turret clean off the Centurion, and split the mantlet of the Conqueror in half. HESH could also serve as a dual-use round just as capable of engaging enemy armor as for use as a high-explosive round against buildings, enemy defensive positions, or soft-skinned targets.

Stage 1

In a 1951 Ministry of Supply: Fighting Vehicle Division ‘AFV Development Report’ – regarding the development of an AFV mounting of the 183 mm gun – the ‘Stage’ or, ‘Scheme 1’ is described as such:

“Embodies a concentric recoil system in a mounting in trunnions on an undercarriage, the whole of which rests on the existing turret race rings. No crew protection is provided and one prototype only will be made to obtain experience of firing such a large gun from the Centurion hull.

It is anticipated that although all round traverse will be possible, firing will be confined to a limited angle forward on either side of the fore and aft line.

Prototype should be completed by 31st December, 1951”

The Stage 1 was built as a test vehicle, as such, it lacked a few components. On the Stage 1, a bespoke platform was constructed that was installed over the original turret ring. This platform was a solid floor, did not incorporate a basket, and was not, in any way, enclosed. The L4 gun was installed in a rigid mount and was completely fixed in elevation. The platform was capable of full horizontal traverse, but firing would be restricted to a limited arc over the front and rear of the vehicle. As mentioned in the report, the gun used a concentric recoil system. This utilized a tube placed around the breech end of the barrel, acting as a space-saving alternative to traditional recoil cylinders.

Two down view of the FV4005 ‘Stage 1’ at ‘Workshop 5’. Note the concentric recoil system at the breech end of the gun, and the gunner’s seat on the left of the gun. Photos: The Tank Museum, Bovington

Space on the platform was limited, as such, there were only positions available – presumably – for the gunner and loader. The gunner was seated on the left of the gun in a well-padded seat complete with a back-rest. Behind him was a large rack for ammunition stowage. The fact that the gun was fixed in elevation allowed the installation of a mechanical ‘loading assist’ device to help the loader handle the combined 233 lb (105.5 kg) weight of the ammunition by aligning it with the breach. This was not an automatic loader as it lacked a rammer. There was no seat for the loader. The driver’s position – the front right of the hull – was unchanged.

A look at the breach end of the L4 and with the ammunition rack on the left, and the ‘loading assist’ on the right. Photo: The Tank Museum, Bovington

The only other changes to the Centurion hull were the addition of a large recoil spade at the rear and a large folding travel lock or ‘gun crutch’ to use the British term. The spade was used to transfer recoil forces from the chassis directly to the ground, easing the strain on the suspension. When the vehicle was in position, it would be lowered to the ground. When the gun was fired, the spade provided a back-stop by digging into the ground.

Rare image of the ‘Stage 1’ traversing a vehicle-deployed bridge. Note the large ‘gun crutch’. Photo: Ed Francis

The ‘Stage/Scheme 1’ was subjected to numerous firing trials. Despite some issues with the concentric recoil system, the trials were a general success. Work then progressed to the ‘Stage/Scheme 2’ vehicle.

Stage 2

In the same 1951, Ministry of Supply: Fighting Vehicle Division ‘AFV Development Report’, the ‘Stage/Scheme 2’ was described as the following:

“Embodies two conventional recoil systems with a hydropneumatic recuperator and an independent run out control. Undercarriage similar to above [Stage 1] but of fabricated construction.

A superstructure for crew protection will be provided but weight considerations will preclude more than a limited degree of splinter protection.

A sight is being designed in which the body is fixed with relation to the gun mounting, and internal moving parts apply angle of sight, target elevation and correction for trunnion tilt. The range scale is visible in the sight eyepiece.

Layout designs have been prepared and details will be completed shortly.

A prototype should be available by March, 1952.”

The Stage 2 was built closest to what a production version of the FV4005 would consist of. As such, a number of changes were made between the two Stages. The biggest change was the design and construction of a fully enclosed turret to the form of little more than a large box. The loading assist for the loader was also deleted, and the concentric recoil system was replaced by a hydropneumatic type.

Original blueprint of the FV4005 ‘Stage 2’. Photo: Ed Francis

The turret was welded and fabricated from ½ inch (14 mm) thick steel and was there to protect the crew from small arms fire and shell splinters. As this was intended to be a second line vehicle that would keep out of the range of enemy AFVs, the FV4005 did not need really thick armor. Also, with the addition of this impressive gun, the chassis and engine could not take any extra weight. The turret was split into two parts: a sloped face and a completely boxed rear end. The turret face was mantletless, with a large face-plate angled at a very shallow angle. The cheeks were also slightly angled. These angled sections terminated in completely vertical turret walls and a flat roof. The roof stepped up as the rear section of the turret was taller and box-like, with external structural ridges. Internally, this rear section was where the ammunition was stowed against the walls. In total, 12 rounds were carried.

There were two hatches on the roof and one large door on the rear. The roof hatches were two-piece and, in front of them, were two single periscopes installed in the turret roof. The large rear door was used for crew access, but it was also used for ammunition resupply via a winch and rail. Charges would be placed on the rail and then winched into the turret. Turret crew would consist of four men including the gunner and commander. As the loading assist of the Stage 1 was deleted on the Stage 2, two loaders were required. One loader would handle the charge, the other the projectile.

A view of the large door at the rear of the turret showing the resupply rail. Note also the breech just visible inside the turret. Photo: Ed Francis.

On the turret face, to the left of the gun, was a large square bulge. This was the housing for the primary gun sight. The particulars of this sight are unknown, however, there is a suggestion that it was based on the TZF-12A of Panther fame. This, however, cannot be corroborated. While the turret was capable of full 360 degrees horizontal traverse, firing was limited to a limited arc over the front and rear of the vehicle. This was a safety feature necessitated by the power of the gun.

Like the Stage 1, the Stage 2 featured a recoil spade installed at the rear of the vehicle. However, on the Stage 2, a hand-cranked winch was installed on the rear of the vehicle to lower the spade.

Rear view of the FV4005 Stage 2 showing the recoil spade and winch above it. Photo: Ed Francis

Like the Stage 1, the Stage 2 went through a number of firing trials. Where the Stage 1’s concentric recoil system suffered some faults, the Stage 2’s more typical hydro-pneumatic system operated without issue. In total, 150 rounds were fired during the tests at Ridsdale, Northumberland. In a 1955 Fighting Vehicle Division ‘AFV Development Liaison Report’ of the Ministry of Supply it is stated that: “General functioning [of the Stage 2] has proved satisfactory”.


Despite the general success of the project, the FV4005 suffered much the same fate as the FV215. The feared Soviet heavy tanks, like the IS-3, which these vehicles were designed to defeat, were not being made in the massive numbers expected, indicating a shift in policy to lighter, more maneuverable, and more lightly armored tanks. The need for ‘Heavy Gun Tanks’ like the Conqueror, FV215 and the FV4005 stand-in, from this perspective, was simply becoming absent. Other changes were also taking place as technology-wise, larger caliber guns with their huge ammunition were becoming obsolete by improved anti-armor performance of smaller guns and by the appearance of a new generation of accurate Anti-Tank Guided Missiles (ATGM).

The dismounted turret of the FV4005 Stage 2. Photo: Ed Francis

The FV4005 project was officially canceled in August 1957, around the same time as the FV215. The three constructed prototypes were divided between various establishments. The Stage 1 was given to the Shoeburyness Proof and Experimental Establishment where the turret was removed and the Centurion hull returned to service. One Stage 2 was offered to the Royal Military College for Science, while the Fighting Vehicle Research and Development Establishment (FVRDE) kept the other Stage 2. The Centurion chassis were also likely returned to service. At some point, one of the turrets found its way to The Tank Museum, Bovington, where it sat alone for a number of years before being mated with a spare Centurion hull owned by the Museum. The vehicle now sits as a ‘Gate Guardian’ outside the museum, alongside a Sherman Grizzly.


The FV4005 Stage 2 ‘Gate Guardian’ as it stands today at the entrance to The Tank Museum, Bovington. Photo:

Illustration of the FV4005 Stage 1 with the open top gun platform, produced by Pavel Alexe.

Illustration of the FV4005 Stage 2 with enclosed turret, produced by Pavel Alexe, based on work by David Bocquelet.

Both Illustrations were funded by our Patreon campaign.

Specifications (Stage 2)

Dimensions (L-W-H) 7.82 (without gun) x 3.39  x 3.6 m
(25’7″ x 11’1″ x 11’8”)
Total weight 50 tons
Crew 5 (driver, gunner, commander, x2 loaders)
Propulsion Rolls-Royce Meteor; 5-speed Merrit-Brown Z51R Mk.F gearbox 650 hp (480 kW), later BL 60, 695 bhp
Speed (road) Apx. 30 km/h (19 mph)
Armament QF 183 mm (7.2 in) L4 Tank Gun
Armor 76mm @ 60º upper glacis. Turret, 14mm all over.


2011.2891: Ministry of Supply: Fighting Vehicle Division, AFV Development Progress Report, 1951, The Tank Museum, Bovington
2011.2896: Ministry of Supply: Fighting Vehicle Division, AFV Development Liaison Report, 1955, The Tank Museum, Bovington
2011.2901: Ministry of Supply: Fighting Vehicle Division, AFV Development Liaison Report, 1957, The Tank Museum, Bovington
Vickers Ltd. Account Records, 1928 to 1959 (Provided by researcher, Ed Francis)
Bill Munro, The Centurion Tank, The Crowood Press
Pat Ware, Images of War Special: The Centurion Tank, Pen & Sword Books Ltd.
Simon Dunston, Haynes Owners Workshop Manual, Centurion Main Battle Tank, 1946 to Present.
Simon Dunston, Osprey Publishing, New Vanguard #68: Centurion Universal Tank 1943-2003
David Lister, The Dark Age of Tanks: Britain’s Lost Armour, 1945–1970, Pen & Sword Publishing

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Cold War British SPG Prototypes

Chimera Tank Destroyer (1984)

United Kingdom (1984)
Self-Propelled Anti-Tank Gun – None Built

Chimera was a British School of Tank Technology study design to develop a casemated Armoured Fighting Vehicle (AFV) that could make constructive use of the remaining, dated FV4201 Chieftain Tanks then still in service. It is worth noting that there are several ‘Chimeras’, the UK not being one to throw a good name away and recycled it for several other projects. For the sake of brevity, all reference to Chimera in this text will refer to the 1984 version.
The project was part of the British LAIC (Long Armour Infantry Course), formerly known as the Tank Technology course. It had been renamed due to the expanding mechanization meaning that infantry now had an equivalent need to understand the technical aspects of the equipment they were operating and officers were invited from various Commonwealth nations.
This particular Chimera began in 1984 as part of LAIC number 35 at the Armour School, part of the Royal Armoured Corps Centre at Bovington, Dorset. The course involved a study to find a cheap and effective way to make a Self-Propelled Anti-Tank Gun on the Chieftain chassis that was to utilize new armor and technology but still be cheaper to produce and operate than the new FV4030 Challenger 1 main battle tank that was entering service.


The result was a casemated design; the turret was removed, the gun was built into the hull and traverse was done by moving the whole vehicle left or right, much in the same way as the Jagdpanzer IV or Jagdpanther late war German tank destroyers. This design concept has several pros and cons over conventional turreted tanks. It lowers the overall profile of the vehicle and allows the placing of heavier armor over the front of the vehicle increasing its survivability. It often allows a more powerful gun to be fitted, however, this comes at a cost of only being combat effective to targets approximately 45° in front of it and less able to defend itself against threats to its flank and rear like a turreted MBT. This type of vehicle is ideally used as an ‘ambush’ weapon: laying in wait in a concealed location then changing location as soon as it fires its gun to another preplanned position to avoid detection.
As mentioned above, aiming was done by steering the vehicle to the left or right should the target be out of the vehicle’s primary arc of fire and therefore such machines are particularly vulnerable if the tracks are damaged. Having to start the tank’s engine and move the whole vehicle to bring the gun into position to fire on an enemy vehicle can reveal its position. This is not ideal. As the Germans found out in the Second World War, if used as a defensive vehicle they can excel, however, it’s their unsuitability for offensive deployment that highlights their greatest flaws. Used in place of conventional tanks, they will inevitably struggle against anything not approaching head-on. Finally, as a side note, they tend to be very long which can cause logistics issues and maneuvering issues around bends or corners.
The overall hull of the Chieftain was lengthened and an extra road wheel added to help take the weight of the Chobham frontal armour which was to be twice that of Challenger 1. It also helped to move the centre of gravity more to the centre. One issue found by the Germans and the Russians, particularly in the later heavily armored casemated vehicles, was that the extra frontal weight put undue stress on the forward suspension often resulting in them having steel road wheels at the front. By increasing the overall length of the hull, it helped to alleviate this somewhat.
The weapon was initially designed around the L11 120 mm rifled cannon gun with the early 1980s muzzle reference system mirror and shroud above the muzzle. This is sometimes marked up as the XL30 120 mm gun which was a considerably more powerful 120mm piece originally designed for the MBT-80 MBT. The XL30 also had the advantage of being shorter yet more powerful than the L11 and could use either the old ammunition or the new CHARM rounds entering service.
The frontal armor was incredibly thick for its time. It was 610 mm to 700 mm of Chobham armor on the upper half of the glacis angled at 20° or the equivalent of about 1400 mm of conventional Rolled Homogeneous Armor (RHA), yet considerably lighter at 2141 kg per ‘cheek’. The lower front of the vehicle was 110 mm of steel at 34° for 132 mm effective frontal plate, enough to stop cannon fire and older Soviet era 100 mm rounds at a distance but vulnerable to more modern rounds. It was envisioned such a vehicle would be deployed hull down ideally, therefore the lower plate would be out of sight and could not be targeted.
The roof section or slope leading up to the midway point was also conventional steel but 122 mm of it angled back at 80° for nearly 700 mm effective armor. The side armor was split between very thick on the upper half and thin on the lower half. Above the track line it was 310 mm thick along the sides for the first 50% of the hull and then dropped to 40 mm for the latter half. The lower side armor remained the same as Chieftain at 40 mm. The rear, back deck and bottom were 25 mm each. Two ‘bazooka’ plates protected the tracks along the sides and these were overlaid with 30 mm applique layers over the first 2/3 of either flank. The total armor weight for the vehicle was 32.5 tons.
Power was supplied by a late model L60 multifuel engine, likely to have been the 12A/N model (formerly known as 14A), giving at 750bhp. By this time, many of the older issues with the L60 had been rectified and although still somewhat temperamental its performance had increased dramatically over the earlier engines. It was also proposed to fit the Rolls Royce MBT-80 engine in this vehicle, replacing the L60. The MBT-80 engine was a 1500 hp unit able to squeeze 2000 hp when required (a less ambitious version of 1200-1500 hp ended up in the Challenger).
The crew was to consist of four men: the commander and gunner on the right hand side; the driver and loader on the left hand side. Both commander and loader have their own hatches which double as entry exit for the gunner and driver who does not have a conventional hatch. Optics were provided by 4 episcopes for the commander and 5 for the loader, the gunner had his own day/night thermal system. Close protection was given by a 0.5″ heavy machine gun remote weapon station located either over the main gun or to the side of the loaders hatch.

A handmade drawing of the Chimera 1984 tank destroyer, made in 1984. It closely matches drawings from official documents and is probably an original piece relating to the project – Source:


The vehicle was built up as far as a large model and presented before a board of MOD and UK leading tank experts in 1985, where it was viewed as successful in achieving the targets set and the project was effectively filed away. No orders were given for modifications to start on the remaining FV4201 Chieftain Tanks still in British Army service. A similar but later design for a casmated Chieftain known as the Combat Test Rig or CTR and erroneously as the Jagdchieftain had also been carried out. However, that was part of the FMBT-70 program and unrelated to this project.

Side note: Tank versus tank

Tank Versus Tank: The Illustrated Story of Armoured Battlefield Conflict in the Twentieth Century is a 1988 book by Kenneth Macksey. It covers tank construction, development, technology, tactics and strategy from the first appearance of the tank on the battlefield up to the Yom Kippur War in 1973. The last chapter of the book deals with a “What-if scenario”, seeing an invasion of NATO by the Warsaw Pact somewhere in Central Europe. For this, Macksey presents the Goliath, an ‘assumed’ advanced tank destroyer used by NATO forces. However, the images presented are of the Chimera 1984 tank destroyer! The Goliath-Chimera is described as being able to reliably survive a frontal hit from the latest Soviet APFSDS rounds while taking out the latest Soviet MBTs at more than 1000 m. This is one of the few cases of a fake ‘fake tank’ in AFV history.

A 1990s battlefield envisioned. The NATO forces are on the left, with the Goliath-Chimera tank destroyer in the small village. Source: Tank versus Tank

Side view of the Goliath-Chimera tank destroyer. Source: Tank versus Tank

Beautiful illustration showing the Goliath tank destroyer in combat. Source: Tank versus Tank

A 3D model of the Chimera tank destroyer, probably done by a private modeller. Source – Quora


Armament 120 mm XL30
Armor Front Armor: 610-700 mm of Chobham armor (1400mm RHA equivalent)
Crew 4 (driver, commander, gunner, loader)
Propulsion Late model L60 multi fuel engine (likely the 12A/N model developing 750 bhp)
Total production None built


CHIMERA: School of Tank Technology
LAIC: Armour magazine
Kenneth Macksey, Tank Versus Tank: The Illustrated Story of Armoured Battlefield Conflict in the Twentieth Century

The 1984 Chimera tank destroyer in NATO colors. Illustrated by Jaroslaw “Jarja” Janas, paid for with funds from our Patreon campaign.

Cold War British SPG Prototypes

Excalibur Light Airborne Tank Destroyer

United Kingdom (1960)
Light Tank Destroyer – None Built

School of Tank Thought

The Excalibur was a British light airborne tank destroyer designed at the School of Tank Technology in the 1960’s. The project called for a machine that weighed not more than 30 tons, was able to fit inside a Royal Air Force (RAF) Blackburn B-101 Beverley heavy transport aircraft and was fully amphibious. The vehicle was to have excellent mobility, mount a weapon capable of destroying any Soviet tank of the period and offer as low a profile as possible. During this period, the primary threat to NATO was the Warsaw Pact (composed of the USSR and its satellites) and, more importantly, it’s vast tank formations which were massed along the East German border. Many vehicles studied or designed in the School of Tank Technology during the 1960s focused on manoeuvre and destroy tactics with rapid reaction airborne vehicles being sought after to plug the expected Soviet breakout tactics.

Blackburn B-101 Beverley heavy transport aircraft. The Excalibur was meant to fit inside it.

Legendary Name

This vehicle is named after the legendary sword of the mythical English King, Arthur. It was the sword the King “pulled from the stone”, although different versions of the Arthurian Legend say it was given to him by The Lady of the Lake. The legend has it that after the death of the mythical King, it was thrown back into to the Lake from where it came, with the Lady retrieving it.


To this end, the designers chose to go with a quite unusual configuration. Rather than choose the standard casemated layout that many opted for in this time period, the engineers chose to mount a semi-rotating turret on the front of the tank chassis to allow for maximum gun traverse whilst keeping a relatively low profile. This design overcame several core problems with casemated designs, notably their weakness to immobilizing factors. Casemated or turretless tanks with the gun mounted in a frontal superstructure rely on their tracks to pivot and make adjustments before firing. Any damage or terrain that prevents this effectively neutralises the vehicle’s offensive ability as their gun traverse is often very poor once immobile. By having a front mounted turret with 45° arc of fire to either side, the Excalibur overcame this problem as it no longer needed to rely on hull adjustments to bring its weapons to bear and this, in turn, would help to lower its overall signature and thus increase it survivability.
In order to keep combat weight down to meet the criteria of fitting and being transported in the Beverley aircraft, the developers went with a light aluminium armor layout. The hull front and turret superstructure were 50 mm of well-angled armor tapering down to 40mm on the lower front plate. The superstructure is 25 mm and 15 mm at the rear. The sides of the vehicle have several stowage boxes built in and a 5 mm separate backing plate remained behind this spaced plate.
Aluminium armor was chosen as it is light enough for making airborne tanks but strong enough to stop what was required in the design specs, notably artillery fragments and machine gun fire. The notion of having a light vehicle with RHA levels of armor to stop APDS rounds and guided missiles of the period was out of the question. Excalibur survivability would come from agility and ambush tactics.
Several weapons were considered in the design but a 105 mm low-pressure gun was chosen. Low-pressure weapons were built to fit onto platforms or chassis that require a large caliber but cannot handle the high recoil pressures or have space for a long recoil. Whilst not ideally used for conventional Kinetic Energy rounds, they work very well with HEAT (High Explosive Anti-Tank) and HESH (High Explosive Squash Head) rounds that require lower velocities on impacting to work effectively. In fact, due to the way they work, the rounds are often better than the high-pressure version as they require less casing meaning increased HE filler. Low-pressure guns do require the gunner to compensate the large drop of the shell over larger distances in order to hit far-away targets. The range of such a weapon is also significantly smaller than that of a high-pressure gun. Although recoilless rifles have similar performance to low-pressure guns in terms of velocity, they are unsuitable for any vehicle with an enclosed space, such as Excalibur. Close protection was provided by a pintle mounted heavy machine gun and a coaxial pair consisting of a 0.5 (12.7 mm) and a 0.3 (7.62 mm) machine guns.
Despite the front mounted weapons, the center of gravity was fairly good and the weight at the nose end not excessive due to the use of aluminium armor and the fact that low-pressure guns are much lighter than their high-velocity counterparts.

Swingfire missile. The Excalibur was meant to be able to mount eight such missiles for AT duties.
Excalibur could also come fitted with Swingfire missiles in the main body. If required, these would be in a series of bins mounted in the boxy body above the tracks. With Swingfire’s ability to change its course by 90° in the first second of firing (something no other ATGM has been able to emulate), it would allow the Excalibur to fire from a defiladed position (behind a hill or ridge exposing little if any of the vehicle) knocking out any tank with its 800 mm of penetration but these fittings were an optional extra. A later series of designs drawn up to a General Staff Operational Requirement (GSOR 1006) had the Swingfires mounted in several positions including along the sides and top racks. Other guns were also considered, from 76.2 mm pieces with drum fed magazines and long HV 105 mm or even 120 mm weapons.
Power was provided by a Leyland L50 multi fuel two stroke 580 bhp engine that ran on diesel or MT80 petrol delivering a top road speed of 48 mph (77 km/h) via an Allison XTG 411-3 automatic transmission with a road range of 318 miles (611.5 km). Suspension was torsion type and the running gear consisted of 5 pairs of double road wheels with the 22 inch (55.8 cm) rubber, brushed steel tracks supported by four return rollers. The engine also had one more feature; it had a built-in waterjet system. This allowed the Excalibur to cross large bodies of water relatively quickly as the whole system required no preparation being inherently amphibious.
The crew of three were all based in the turret at the front, the commander and gunner to the right and loader/radio operator to the left. The gunner doubled up as the driver as the Excalibur was never designed to shoot on the move and the whole system could be switched from gunner to mobility mode at the flick of a switch.

Just a Peculiar Idea

The Excalibur itself was never built however the GSOR 1006 project did see the plans dusted off and further designs drawn up for a service vehicle. However, this too never entered service.

Shrivenham, one of the places where the School of Tank Technology was based.

Excalibur specifications

Dimensions 25.10 x 8.11 x 11 ft
(7.6 x 2.47 x 3.3 m)
Total weight, battle ready 60,000 lbs (30 tons) max
Crew 3 (commander, gunner/driver, loader/radio operator)
Propulsion Leyland L50 multi fuel two stroke 580 bhp
Transmission Allison XTG 411-3
Suspension Torsion bars
Steering T-bar mechanism
Speed 48 mph (77 km/h)
Ground clearance 16 in (40.6 cm)
Track 22 inch (55.8 cm) rubber, brushed steel
Armament 105 mm low pressure gun
2 x 7.62mm machine guns
12.7mm HMG
Optional: 8 x Swingfire missiles
For information about abbreviations check the Lexical Index


School of Tank Technology (STT) Excalibur, British National Archives

The Excalibur Light Tank Destroyer. The unusual front turret is clearly visible. Illustrated by Bernard “Escodrion” Baker. Illustration paid for thanks to Patreon donations.

Cold War British SPG Prototypes

Chieftain Casement Test Rig (CTR) SPG

United Kingdom (1972)
Self-Propelled Gun – 1 Prototype Built

The Chieftain CTR ‘Jagdchieftain’

This prototype British Cold War self-propelled gun has received the popular nickname of the ‘Jagdchieftain’ because of its similarity to the WW2 German Jagdpanther anti-tank self-propelled gun (SPG). Its correct designation is the Chieftain Casement Test Rig (CTR). This is the name given to the vehicle by William Suttie in his book ‘Tank Factory.’ The Tank Museum, Bovington call it the ‘Concept Test Rig.’
It was a 1972 joint project between UK and the Bundeswehr (West German Army). In Germany, tank designers had been experimenting with the Panzer VT1-1 and VT1-2 Leopard 2 chassis SPG armed with twin 120 mm cannons. The Casement Test Rig (CTR) had a semi-fixed single gun. The gun was set in a casement hull superstructure on a Chieftain tank chassis. A lot of aluminum was used in an effort to reduce weight.
Jagdchieftain Concept Test Rig SPG prototype
This prototype test vehicle is often called the Jagdchieftain but its correct name is the Concept Test Rig (CTR) – Photo: Colin Rosenwould Tankfest 2011
In the early 1970s, NATO believed that to deal with an overwhelming force of Soviet armor the Allies would fall back while inflicting as many casualties as possible until more troops and tanks could be shipped into Europe from America and Britain. The designers wanted to create an anti-tank SPG that had a low profile, a powerful gun and that could travel just as easily in reverse as forward. It was to be the ideal ambush weapon that could wait for the enemy to appear in a concealed location then open fire inflicting as much damage as it could before quickly reversing out of danger to its next preplanned ambush location. For survival, the front armor would be thick and sloped.
This was not the first time a British casemated self-propelled gun had been proposed. There were the class 40, 50, 60 tanks as well as rival Vickers A,B,C,D designs and the Alvis external concept. None progressed further than wooden mockups.

The Engine

Underneath the superstructure is basically a conventional Chieftain chassis, In order to conform with British and German requirements it could be fitted with the British Leyland L60 engine or the Leopard tank ten cylinder MTU multi-fuel power pack preferred by the Federal German Army of that time. The chassis was slightly widened to accommodate the MTU power pack.
The exhaust system was slightly different to that on the operational Chieftain tank in that it had a raised box on top of the chassis
The exhaust system was slightly different to that on the operational Chieftain tank in that it had a raised box on top of the chassis. The rear stowage boxes are missing – Photo: Colin Rosenwould Tankfest 2011

The Armor

The front sloped glacis plate was to be heavily armored against all current and future anti-tank (AT) weapons in the 1980-90s. Had the ‘Jagdchieftain SPG’ entered production, it seems probable that the new Chobham armor would have been applied. This was not fitted to the prototype but was simulated by the addition of 5 tons of lead plate covered in sheet metal.
The prototype’s superstructure was fabricated from aluminum in order to try and keep the weight down but even so, the Mechanised Vehicle Experimental Establishment (MVEE) estimated the final weight would be 55 tons. The term ‘Chobham armor’ has become the common generic term for composite armor developed in the 1960’s at the British tank research center on Chobham Common, Surrey, England.
Front view of the Chieftain Casement Test Rig (CTR) SPG
Front view of the Chieftain Casement Test Rig (CTR) SPG’s sloped front armour plate prior to the gun being fitted
The Casement Test Rig SPG was based on the Chieftain tank FV4211 nicknamed the “Aluminium Chieftain”. After the project was canceled, the CTR was kept in storage to monitor the hull welds to gain information on deterioration of the aluminum armor.

The Gun and Crew

The main armament was intended to be the British 120 mm L11 rifled gun, although for trial purposes only a dummy tube was installed. Unlike the Swedish S-Tank, which had a fixed gun, the British CRT self-propelled gun concept allowed the gun to elevate from −10 to +20° and traverse +/− 2°, allowing fine tracking without moving the hull.
The crew of three comprised a commander and two driver/gunners. One of the drivers and the commander were able to drive the vehicle forward from their positions, while the second driver/gunner had a rear vision block to allow him to drive it backwards, so they could reverse away from the enemy after ambush without showing their rear. This enabled the vehicle to use the ‘Shoot and Scoot’ tactic.
Development of the Casement Test Rig SPG was inspired by Swedish S-tank that had the same driving configuration. Two of these Swedish vehicles had been tested at Bovington in 1968. During the development of the CRT a further ten S-Tanks were borrowed for a more intense assessment during a military Exercise called ‘Dawdle’ in Germany.


The Concept Test Rig was assembled by the Fighting Vehicle Research & Development Establishment (FVRDE) at Chertsey but trials at Woolwich confirmed what had been seen in Germany on Exercise Dawdle: accurate gun laying was inferior to a turret in terms of speed of engaging targets and that it could not fire accurately on the move. The project was dropped and the vehicle was eventually sent to the Tank Museum at Bovington in 1990.
Jagdchieftain Concept Test Rig SPG prototype
Chobham armor was not fitted to the prototype, but it was simulated by the addition of 5 tons of lead plate covered in sheet aluminium alloy – Photo – Colin Rosenwould Tankfest 2011

FV217 Conqueror self-propelled gun proposal

This design did not get past the wooden model stage. A prototype was not built mainly for the same reasons the Chieftain Casement Test Rig (CTR) SPG project was dropped. Some call it the JagdConqueror because of its resemblance to the German WW2 Jagdpanther but that was never its official name. It was called the Conqueror Casement Test Rig (CTR) Self-propelled gun (SPG). It was to be fitted with a 120 mm gun.
It seems a strange thing to do as the Conqueror tank was already armed with a 120 mm gun but this vehicle would have been simpler and cheaper to build (a factor that would appeal to politicians). It would also have had a lower profile and thus have been harder to target. It would have been an ambush weapon that would sit in wait for advancing Soviet tanks and fire at them from cover, when they came within range of its gun. It would not have been as adaptable as the tank version.
FV217 Conqueror self-propelled gun

CTR Specifications

Dimensions (L-W-H) 24’6″ (without gun) x 11’5″ x 9’5″
7.51 (without gun) x 3.5 x 2.89 m
Total weight, battle ready 55 tons (11000 Ibs)
Crew Commander and two drivers who also serviced the gun.
Propulsion British Leyland diesel L60, 695 bhp or
Leopard tank ten cylinder MTU multi-fuel power pack
Speed 48/30 km/h road/cross-country (29.82 mph/18.64 mph)
Range/consumption 500 km (310.68 miles)
Proposed Production Armament British 120 mm L11 rifled gun
Proposed Production Armor Chobham Armor
Total production 1 prototype


Ed Francis – The FV3805 Restoration Project
Chieftain by Rob Griffin
Colin Rosenwould
Tank Museum, Bovington, Dorset, England
Steve Osfield
Tank Factory, William Suttie, 2015


Illustration of the Chieftain test rig by David Bocquelet
Jagdchieftain Concept Test Rig SPG prototype
Side skirts were used to protect the side of the vehicle. If it had entered production, Chobham Armour panels would have been attached on top of the skirt panels – Photo: Colin Rosenwould Tankfest 2011
Jagdchieftain Concept Test Rig SPG prototype
The gun and gun mantlet on the Concept Test Rig SPG were not real units – Photo: Colin Rosenwould Tankfest 2011
Jagdchieftain Concept Test Rig SPG prototype
The front stowage unit behind the head light on top of the track guard is missing on the CTR prototype – Photo: Colin Rosenwould Tankfest 2011
Jagdchieftain Concept Test Rig SPG prototype
The top mesh exhaust box was not used on the production models of the Chieftain tank – Photo: Colin Rosenwould Tankfest 2011
Jagdchieftain Concept Test Rig SPG prototype
The downward pointing exhaust pipe and rear stowage box are missing – Photo: Colin Rosenwould Tankfest 2011
Jagdchieftain Concept Test Rig SPG prototype
The rear skirt panel has been removed. You can see the support bracket – Photo: Colin Rosenwould Tankfest 2011
Handlebar steering system
The handlebar steering concept was used on the CTR. It was also tested on the FV432 Armoured Personnel Carrier (FV432 APC) – Photo: Ed Francis
Chieftain Casement Test Rig prototype without the gun fitted
Chieftain Casement Test Rig prototype without the gun fitted
Top view of the crew hatches and engine covers on the Chieftain CTR
Top view of the crew hatches and engine covers on the Chieftain CTR self-propelled gun

Cold War British SPG Prototypes


United Kingdom (1956)
Self-Propelled Gun – 2 Prototypes Built

The Design

The vehicle itself started back in the late 1950’s based upon the idea of using the hull of a Centurion tank and fitted with a BL 5.5 inch QF field gun (140mm howitzer) in a built up casemate on the hull. The idea was a good one offering commonality of automotive parts with the Centurion tank which was the main tank in service with the British Army at the time. A wooden mock-up of the vehicle had met with approval and two prototypes P1 and P2 were manufactured and underwent testing.
FV3805 Wooden mock up
This is the wooden mock-up of the Centurion FV3805 Artillery SPG prototype
The project eventually lost out by the early 1960’s to the FV433 self-propelled gun known commonly as the ‘Abbot’ and both prototype Centurion FV3805 SPG P1 and P2 were thought to have been sold for scrap. The Abbot was chosen because the FV3805 SPG was not air-portable and with NATO standardization of 105mm and 155mm guns the British 5.5 inch gun (140mm) was being made obsolete. With a limited traverse of the gun it was an inferior design to the smaller, lighter and more capable Abbot anyway.
The vehicle is built ‘backwards’ very similar to the WW2 Archer 17pdr SPG. The engine and gearbox are at the front and the superstructure built over the front of the machine but facing over the engine deck. The driver position was moved to the center of the vehicle on the left side.
wooden mock-up of the Centurion FV3805 Artillery SPG prototype in firing position
Wooden mock-up of the Centurion FV3805 Artillery SPG prototype in firing position
Following the unsuccessful trials P2 had its 5.5 inch gun and mounting removed and a steel plate with vision port welded over the hole in the front of the superstructure. Centurion FV3805 SPG P2 lived on in service as an Artillery Range Observation vehicle sporting the name ‘Major Picton’s Palace’ until sometime in the 1970’s when again it has vanished from military records. Research is still trying to locate the fate of P1 which is still lost. (Information – Andrew Hills)
Centurion FV3805 artillery self-propelled gun prototype
Centurion FV3805 artillery self-propelled gun prototype

The British BL 5.5 inch Artillery Gun

This artillery field gun was produced between 1941 to 1945. It weighed 13,647 lbs (6,190kg) and had a barrel length of 13ft 9in (4.19m). Its caliber was 5.5 inch (140mm). It fired a high explosive HE shell that weighed 100 lbs (45.5kg) and a smaller one that weighed 82 lbs (37kg). The 100 lbs shell could be fired at a maximum range of 9.2 miles (14.81 km). The lighter 82 lbs shell could be fired at a maximum range of 10.28 miles (16.55 km). The letters BL stand for ‘breach loading’.
FV3805 Centurion Artillery SPG gun crewFV3805 Centurion Artillery SPG gun crew
It was fitted with a Welin breech and Ashbury mechanism with a hydro-pneumatic recoil system. It had a rate of fire of two rounds per minute. The 100 lb shell was fired at a muzzle velocity of 1,675 feet per second (511 m/s) and the 82 lb shell was fired at 1,950 feet per second (590 m/s).
It fired two part ammunition. The high explosive HE shell was loaded first followed by the propellant charge canister that would have the correct amount of powder bags in it for the range of the target. It could also fire 100 lb smoke or colored flare marker shells. The normal HE fuze was No 117. In late 1944 a VT fuze T100 became available.
This gun was first used in the deserts of North Africa in 1941. Most British, Polish and Commonwealth forces were equipped with this gun. The normal organization was an artillery regiment of 16 guns organized into two batteries. It continued to be used during the cold war in conflicts like Korea. It was purchased by many different nations. Both Pakistan and India used this gun in their border wars. In the British Army it was replaced by the L121 FH-70 155mm towed Howitzer. It remained in UK service with Territorial Army regiments until 1980.
The 5.5 inch QF gun fitted inside the enclosed casement on the top of the Centurion tank chassis
The 5.5 inch QF gun fitted inside the enclosed casement on the top of the Centurion tank chassis


The following information was found in an original document covering the ammunition stowage on the FV3805 SPG.
(a) At least 25 HE rounds (fused) and 5 HESH (fuzed) are to be carried in the SP. It is desired to carry 35 HE and 5 HESH.
(b) Provision shall be made fro the stowage of:-
12 Bulk packed VT Fuzes
5 Cartridges charge 2 (7 if 35 rounds HE are stowed)
12 Cartridges charge 4 (17 if 35 rounds HE are stowed)
18 Cartridges charge super (27 if 35 rounds HE are stowed)
40 Tubes P.S.A
768 rounds .303 ball SAA
288 rounds .303 tracer

The 105mm gun

At one point in 1964, the Centurion FV3805 SPG was tested with a 105mm gun. The following reference was found on official records “16.2.64. Abbot mounting fitted to 5.5in SP (P2). Proofed at K Battery at 7½°. Recoil at 14 in – steady’”

MOD Shoeburyness

The following account is from Roger Walton who actually drove the Centurion FV3805 artillery SPG prototype whilst he was in the British Army: – In 1977 whilst serving in Northern Ireland I noticed a posting requiring a driver of tracked vehicles. I loved driving so I put my name down. In February 1978 I arrived at the Army MOD Shoeburyness and Foulness Defence Evaluation and Research Agency [DERA]* weapons testing complex, near Southend-on-Sea in Essex.
It was not a glamorous posting. I was in a team of 3 drivers, a Lancer from the 16/5th, one from 3rd Royal Tank Regiment RTR and myself being Queens Own Hussars, plus REME and 120 gunners.
It was my first time in a weapons proofing establishment and I was expecting to see loads of Chieftain tanks. My first Monday at the tank workshops I was horrified to learn that they only had one Chieftain, a rare mark one which was being used to calculate various things which the civilian boffins thought we didn’t need to know.
FV3805 being driven at the MOD Shoeburyness
The FV3805 being driven at the MOD Shoeburyness and Foulness Defence Evaluation and Research Agency weapons testing complex, near Southend-on-Sea in Essex
Back at the workshops, I was introduced to a number of AFV ‘funnies’ used for towing, recovery and as gun platforms. The Centurion FV3805 SPG was sat in yard. Never having seen this vehicle before I was keen to find out more so I asked after the beast.
It was explained that it was a prototype and had been intended for the artillery. At this time it was a none runner fitted with a 105mm gun from an Abbot Artillery SPG.
It was soon sanctioned by the powers that be to get it running so it could be used as an ammunition carrier whilst out on the sands firing range.
It did not take long to get her back in a running condition. I soon learned the quirkiness of this vehicle. The engine and gearbox were what I normally found in an old Centurion tank, except the drive was all reversed.
The gun was on a fixed/limited traverse facing over the engine decks. The driver sat to the left of the gun. The drivers control sticks, gear stick had all been shortened.
It didn’t drive any differently to a normal Centurion tank, but I do remember having a limited view to the front. I was totally blind due to the gun being on my right. You could see bugger all to the right. Also due to the higher than normal driving position obstacles had to be carefully negotiated. As a driver you had a small hatch which you had to be careful using due to the height from the ground.
The only obstacle on the base at this time was the sea wall. As you crested this we had to turn right to go onto the beach drive 100 yards or so to get onto the ramp onto the sands.
It was being used to carry and store ammunition for other vehicles being tested at the base. I remember one time it being used to take ammunition onto the beach to supply an American M110 that was being put through tests. After delivering the ammo the FV3805 withdrew back down the beach during the live firing of range safety rules.
*DERA is now known as QinetiQ (pronounced kinetic)

Artillery Observation Vehicle

At some point, the 5.5 inch gun was removed from the prototype FV3805 and the vehicle was converted into an artillery observation vehicle to be used on the firing ranges. The holes left by the removal of the gun were blanked off with armor plate and an observation glass panel was added instead. It was painted light blue instead of the traditional British Army olive green so it was noticeable on the firing range. It was eventually transported to Duxford when it was no longer needed where it stood out in the rain, sun and snow for a number of years.
FV3805 Centurion Artillery observation vehicle
The FV3805 Centurion (on the right) was painted light blue and used as an artillery observation vehicle after the 5.5 inch gun was removed. On the left is the FV207 Conqueror SPG prototype fitted with a 4.5 inch naval gun. Other guns were tried. The protective armoured casement has not been constructed yet.(MOD Shoeburyness beach firing range 5th June 1984.)

The Centurion FV3805 SPG P2 restoration project.

FV3805 P2 reappeared on the Isle of Wight, in Southern England at the Military Museum. Here she has sat outside in the salty air rusting away quietly and becoming rather sorry looking until 2015.
Phase 1 of the restoration; moving the vehicle under cover to dry out has been completed. The next steps will be to organize the stripping of the paint and components from the tank for restoration.
Phase 2 is getting the vehicle running. The biggest hurdle being the Rolls-Royce Meteor MkIVB engine which on inspection appears to be completely seized and likely is unrepairable. The gearbox is intact but needs an overhaul. The wheels and tracks are all complete.
Phase 3 is fitting the gun. The gun itself is problematic. There is a lack of 5.5 inch guns for sale at the moment.
The focus at the moment is on restoration of the running components so she can be shown to the public. The FV3805 Restoration Project is on Facebook at
(Information – Andrew Hills)
FV3805 awaiting restoration
FV3805 awaiting restoration on the Isle of Wight, England (Photos: The Mighty Jingles)

Ammunition stowage

At least 25 high explosive HE rounds (fused) and 5 HESH (fuzed) rounds are to be carried in the self-propelled gun. It is desired to carry 35 HE and 5 HESE.
Provision shall be made for the stowage of:-
12 Bulk packed VT fuzes
5 Cartridges charge 2 (7 if 35 rounds are stowed)
12 Cartridges charge 4 (17 if 35 rounds HE are stowed)
18 Cartridges charge super (27 if 35 rounds HE are stowed
40 Tubes P.S.A.
768 rounds .303 ball SAA
288 rounds .303 tracer.


Dimensions (L-W-H) 7.82 m without gun x 3.39 m x 3 m
(25ft 7in x 11ft 1in x 9ft 9in)
Total weight, battle ready 50 tons
Crew 4 (commander, driver, gunner, loader).
Propulsion Rolls-Royce Meteor; 5-speed Merrit-Brown Z51R Mk.F gearbox 650 hp (480 kW), later BL 60, 695 bhp
Speed 48/30 km/h road/cross-country (29.82/18.64 mph)
Range/consumption 190 km (118 mi)
Armament British BL 5.5 inch Artillery Gun
Gun depression 3 degrees
Gun elevation 70 degrees
Gun traverse 30 degrees left and right from centre line
Rate of fire 3 rpm for 10min or 1 rpm for 3 hours.
Armor 35mm-195mm (17mm-58mm on cab)
Ammunition used 100 lb HE shell, 82 lb HE shell, 100 lb Smoke shell, 100 lb coloured flare shell.
Ammunition Stowage 76 shells and 96 charges
Total production 2 prototypes


Ed Francis – The FV3805 Restoration Project
The Wight Conflict and Remembrance Museum
The National Archives, Kew Memorandum TR 4/57, TR 1/58 Effect of 5.5 inch gun-muzzle blast on FV 3805
The Centurion and variants on Wikipedia
BL 5.5 inch Medium Gin on Wikipedia


Centurion FV3805 artillery SPG
Wooden mock-up of the Centurion FV3805 artillery SPG. Notice the drivers escape hatch and vision slit to the left side of the 5.5 inch gun.
Centurion FV3805 artillery SPG prototype with limited travers turret built inside a fully covered casement.
Centurion FV3805 artillery SPG prototype with limited travers ‘turret’ built inside a fully covered casement.
Centurion FV3805 SPG with the 5.5 inch gun at full elevation
Centurion FV3805 SPG with the 5.5 inch gun at full elevation.
side view of the Centurion FV3805 SPG with the 5.5 inch gun
Side view of the Centurion FV3805 SPG with the 5.5 inch gun.
Centurion FV3805 SPG ammo storage racks on the right side of the vehicle
Centurion FV3805 SPG ammo storage racks on the right side of the vehicle.
Centurion FV3805 SPG ammo storage racks behind the drivers position
Centurion FV3805 SPG ammo storage racks behind the drivers position.
View of the rear hatch at the back of the Centurion FV3805 SPG
View of the rear hatch at the back of the Centurion FV3805 SPG with more ammo storage racks on both sides of the vehicle.
Centurion FV3805 artillery SPG in firing position
Centurion FV3805 artillery SPG in firing position at MOD Shoeburyness.
The only photo of the Centurion FV3802 SPG to show the top/rear hatch intact and open
A photo of the Centurion FV3805 SPG showing the top/rear hatch intact and open.
Centurion FV3805 SPG showing the top/rear hatch intact and open.
Centurion FV3805 SPG showing the top/rear hatch open.
Centurion FV3805 SPG showing the top/rear hatch closed
Centurion FV3805 SPG with the top/rear hatch closed.

Artillery observation vehicle

Artillery observation vehicle centurion FV3805
Artillery observation vehicle centurion FV3805 with the 5.5 inch gun removed. An observation window was inserted into armour plate to fil0e the gap left by the gun’s removal

Restoration project

This photo confirms that the last remaining FV3805 Centurion PG was the P2 prototype
This photo confirms that the last remaining FV3805 Centurion PG was the P2 prototype. It is not known what happened to the P1. P2 was nicknamed ‘Major Picton’s Palace’. For many years Major Ian Picton was in charge of ‘A’ Section Trials and normally involved with Sands Shoots at MOD Shoeburyness. It was warm inside and was a good place to lurk on a rainy day.
This photograph was taken of the Centurion FV3805 SPG at IWM Duxford before it was moved to the Isle of Wight
This photograph was taken of the Centurion FV3805 SPG at IWM Duxford before it was moved to the Isle of Wight. (Photo – Ossie)
Centurion FV3805 rear hatch
Because the Centurion FV3805 rear hatch is so large it is hoped that when the vehicle is restored to a running condition it will be the first AFV that can offer ‘tank rides’ to veterans and members of the public in wheelchairs.
The Centurion FV3805 SPG was originally painted British Army Green.
The Centurion FV3805 SPG was originally painted British Army Green.
Centurion FV3805 SPG P2 under restoration on the Isle of Wight.
Centurion FV3805 SPG P2 at The Wight Military and Heritage Museum 2015.

May 2019 Update

Tanks Encyclopedia writer Mark Nash visited the Wight Military and Heritage Museum in May 2019 to inspect the progress in the restoration of the Centurion FV3805 self-propelled gun P2. Unfortunatly there has not been any work undertaken on the vehicle for the past four years and, in the words of a staff member “has all but ground to a halt”. It is left out in the open without any covering and spider webs cover the hull. Its condition is deteriorating. This is very sad as it is the only surviving example of this vehicle. The owner has offered to sell it but the price he is asking is very expensive. (There is also an ownership dispute that has not yet been settled). The vehicle used to run but the engine has now seized due to water getting into the engine via the exhausts. Any useful engine parts have been cannibalised.

Looking in through the rear hatch, you can see the Drivers position in the front left corner of the superstructure. (Photograph: Mark Nash Photography)

This tattered piece of tarp weight down by a pallet and old tyre is the only protection the vehicle has from the elements. (Photograph: Mark Nash Photography)

A view of the cannibilised engine through the vehicle’s rear hatch. (Photograph: Mark Nash Photography)

Illustration of the FV3805 Centurion Self Propelled Gun (SPG) prototype by Jarosław Janas