Cold War, United Kingdom

The Charioteer – A Cromwell with a 20-Pounder Gun

The Charioteer is a British tank from the post-Second World War period based on the hull of the Cromwell, modified to carry the large 20-pounder gun as used on the Centurion. This was successfully achieved, and managed to give the Cromwell Centurion levels of firepower.

Considering a few years prior there was a struggle to fit the Cromwell’s intended armament, its a true testament to how, when given the time and resources, obsolete designs can be given a second chance.

Britain created the Charioteer to bulk up Britain’s armored forces to face the formidable threat of the Soviet Union. By fitting this gun to Cromwell hulls, it multiplied the firepower capability of Britain’s tanks.

One version was even fitted with one of the best tank guns of the Cold War, the 105 mm L7 – not bad for a tank that is often said to have been obsolete when it originally entered service in 1944.



The Second World War saw a variety of vehicles developed during the period, and attempts to up gun these vehicles was a natural progression. The Challenger MK 1 and the A30SP were some of these vehicles, but little more than the 17-pounder gun was fitted.

While the 17-pounder was adequate for the war period, the Western Allies realized its limitations following the reveal of the IS-3 and others at the Berlin Victory Parade of 1945. While these tanks eventually proved to be more talk than walk, back then they posed a serious threat, as the Allies had little, if anything that could counter them head on.

This caused many Western nations to create designs in response to the new Soviet heavies – Britain was no exception.

IS-3s at the Berlin Victory Parade of 1945.
Soviet IS-3s roll along Charlottenburg Chaussee in Berlin during the Berlin Victory Parade of 1945.

As always, Britain had the option of simply purchasing US equipment, but they were very keen on not becoming dependent on the US.

At the time they had one key weapon which brought more firepower than the 17-pounder, the 84mm, better known as the 20-pounder. Britain had three such weapons ready in 1945, and was keen to get the type into as many vehicles as possible.

But Britain had just come out of Second World War, and had a long list of vehicles that were already in service, nearly ready or still in development. With the USSR the new enemy, and knowing they now faced hoardes of T-34-85s and heavily armored heavy tanks, they had to decide how to make the most out of what they had.

An A34 Comet
The Comet was Britain’s newest serving tank when the Second World War ended. It is considered a genuinely good design.

Part of this required upgrading older designs with bigger guns to meet the threat.

The Cromwell, Churchill, and Comet were investigated for upgrades. Newer designs, such as the Centurion, were to receive armament upgrades too. At first it was fitted with the 17-pounder, but was quickly updated to receive the 20-pounder.

The biggest vehicle of the bunch, the Conqueror heavy tank, would have the most powerful gun, the 120 MM L1. However the vehicle was not yet ready, resulting in the 20-pounder armed FV221 Caernarvon being created as an interim solution.

FV221 Caernarvon universal tank.
The FV221 Caernarvon was an interesting vehicle. It was temporarily fitted with a Centurion turret during its development, but it would never enter service.

So, Britain now had the Cromwell, Comet and Centurion, with the Caernarvon and Conqueror on the way.

With this, Britain had done its best to transform a random mix of different tanks, old and new, into a force that could theoretically face the Soviets.

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However, while most of the tanks on that list could hold their own against Soviet vehicles, one stands out as rather lacking; the Cromwell.

Combat against the Soviets was expected to be tank-versus-tank, but the Cromwell’s 75 mm gun was incapable of knocking out any soviet tank from the front – lacking the punch to take on even the T-34-85.

A Meteor powered Cromwell at The Tank Museum.
Even for 1944 standards, the Cromwell’s gun was regarded as rather lacklustre. Image taken at The Tank Museum, Bovington.

In fact, the Director of the Royal Armoured Corps said that the Cromwell’s deployment “would be very unpleasant for the formation concerned”. 

So, how do you make a tank from 1944 able to fight the newest Soviet tanks? You stick a big gun in it!

A plan was drawn up for the Cromwell to recieve a new gun, and that gun, of course, was the 20-pounder. This resulted in the focus of this article, the FV4101 Charioteer.

Also, because the Conqueror was still not ready, Britain looked into putting its 120 mm gun onto the Centurion with the Conway project.

Tank, or Tank Destroyer?

It’s worth pointing out at this time that the Charioteer is a tank, not a tank destroyer. This has nothing to do with the coaxial machine gun as often touted but due to doctrine and regimental role.

There is a certain amount of confusion here as during the Second World War there were tank destroyers with the name SP (self-propelled) designed to fight tanks from a distance yet have the mobility to keep up with tanks. These self-propelled guns were operated by the Royal Artillery, not the Royal Armoured Corps. They were ‘tank destroyers’ in role, but not a fixed doctrine, and the term was not used formally.

FV4005 183 mm gun tank.
The British FV4005 had thin armor, a huge turret and a massive gun, designed to fire at the enemy from a distance – yet it was classed as a tank.

The Royal Armoured Corps wanted tanks to destroy tanks, but could not imply they were tank destroyers as to not get mixed up with the Royal Artillery’s role. As a result, vehicles such as the Firefly and Charioteer were classed as tanks.

The system is confusing and remains that way for decades.

Back to the Charioteer.


The Vehicle was initially called Cromwell Heavy AT in development and the FV number 4101 was applied. But it was eventually given the name Tank, Medium Gun, Charioteer to avoid any confusion with the remaining Cromwells in service. 

They took the mixed Cromwell hulls lying around and upgraded them to a common Cromwell VII standard. Extensions were welded into the upper hull sides, enabling the fitment of a turret ring just about large enough for the 20-pounder.

Charioteer in museum.
The Charioteer. Image by Methem CC BY 3.0.

The old turret was removed and a new two-man turret added on top. This was not a desirable arrangement, but it was required as the 20-pounder simply wouldn’t fit inside a three-man turret.

Even though the turret ring was bigger, the gun itself could still not be fired in an elevated position – where the breech would travel past the ring – so the turret’s overall height was increased to accommodate this (a more complex but complete way of solving this issue is with an oscillating turret).

Meanwhile though the gun had an excellent 12 degrees of gun depression, enough to enable hull-down fighting which, combined with a narrow turret face, offered a very small profile, increasing its survivability. 

Charioteer in snow.
From straight on the Charioteer’s turret presented quite a small target.

The lack of armor being just 20-30 mm thick wasn’t as much as a hindrance as one might expect, as the firepower to armor ratio had scaled up so much that conventional armor was mostly redundant. Combat was now dictated by who is spotted first, fires first, and accuracy of the gun, over the ability to survive incoming shots.

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In the two-man turret the commander would operate as the gunner, while a loader sat opposite him and doubled up as the radio operator. The driver remained in the standard position at the front right of the hull.

A .30 caliber machine gun was mounted coaxially, operated by the loader. A small hatch at the back of the turret was used to throw the 20-pounder’s large spent cases out. 

Charioteer turret.
The Charioteer’s turret. Note that there are two hatches, as it only contained two crew. Image by Bukvoed CC BY 2.5.

External fire extinguishers were added, as was a telephone box at the rear for infantry to speak to the commander. A small spotlight and smoke dischargers from the Comet were also added.

Due to the larger ammunition size, the bow machine gunner was removed, much as was done on the Sherman Firefly to increase the storage capacity and additional ammunition kept inside the hull. Even still the Charioteer only carried around 25 rounds, of which the majority were to be APDS (armor-piercing discarding sabot) rounds able to penetrate 266mm of steel at 900 meters (3,000 ft).

The Charioteer inherited the same 27 litre V12 Meteor engine from the Cromwell. It came in at under 30 tons in weight, and had a top speed of 32 mph (51 kph).

Production took place at Robinson & Kershaw in Manchester, who had previously made trains and worked on Churchill tanks. The Cromwell hulls were modified there and the new turrets were made. They mounted the 20-pounder type A at first, then the later type B. The type B can be easily identified by the bore evacuator with a distinctive ridge on it.

Charioteer at The Tank Museum.
Note the angular plate welded to the front of the hull. This covered over the Besa machine gun port. Image taken at The Tank Museum by Mightyhansa CC BY-SA 3.0.

Those fitted with the older type A barrel were given the designation Charioteer Model A and the later ones Model B. Nice and simple.

An order for 630 vehicles was placed in 1951, but it is believed some 442 were converted over during the product run.


During the Cold War the Charioteer, Centurion, Conway and Conqueror were compared and scored on their overall effectiveness.  This looked at the combination of how likely they were to be knocked out, versus how capable they were at knocking out the opposition.

The Conqueror was 20% more effective against the IS-3 than the Centurion Mk III, but offered the same results versus the T34-85 as both tanks were equally effective at knocking it out.

The back of the Charioteer.
The rear of the Charioteer. Note the fishtail exhaust pipes, and the hatch at the back of the turret for discarding spend casings.

The Conway scored lower than the Conqueror, because while the gun was more or less the same, she was taller and had less armor which made her vulnerable. The Conway also scored lower than the Centurion against medium tanks as both were more than capable but her high profile means she lost out.

The Charioteer had the same effectiveness as the Centurion in knocking out the T34-85 and the same weakness against the IS3 – she was less protected but faster to redeploy. She was expected to be roughly equal to the T34-85 as both vehicles had guns capable of knocking the other out comfortably, and similar capabilities.

Charioteer range target.
A Charioteer that has seen better days, after spending time as a range target. Note the Type B 20-pounder barrel. Image by Alan Wilson CC BY-SA 2.0.

In this regard, the additional armor of the much larger Centurion gave it an advantage, and thus Charioteer was only destined to be an interim tank. In later re-organizations, they were moved to the Territorial Army and then sold to other friendly nations.

The primary other users were Finland, who until recently had a fairly large surplus for sale, and others in Lebanon where they saw conflict in several wars. A further batch was sent to Jordan and these differed in having an upgraded turret traverse system and a commander’s cupola with a .50 caliber machine gun as well as different radio sets. 

A Charioteer turret in the Alps.
A Charioteer turret in a fixed position in the Austrian Alps. Image by Hubertl CC BY-SA 4.0.

A single-vehicle was upgraded in the UK with the Royal Ordnance L7 105mm gun for trials in 1969 as a further export attempt, but saw no buyers and the sole remaining vehicle now sits in a private collection in the UK. The change to this gun was straight forward, as the L7 was a bored-out 20-pounder.

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Today there are a fair few charioteers surviving. Several in the UK, Finland have a good number as does Lebanon in various states of disrepair while in Austria the turrets were used in defensive ambush positions.