In addition, 344 Churchills were sent as military aid to the Soviet Union during the Second World War and more than 250 saw active service on the Eastern Front.

Winston Churchill told Field Marshal Jan Smuts "That is the tank they named after me when they found out it was no damn good!

In accordance with British infantry tank doctrine and based on the expected needs of attacking a fixed defensive line, crossing wide trenches, possibly shell-cratered ground similar to First World War trench warfare[7] it was to be immune to the current German 3.7 cm Pak 36 anti-tank guns and carry an unditching beam.

[7] A general outline produced by Woolwich Arsenal was expanded by Belfast shipbuilders Harland & Wolff with advice from the Department of Tank Design.

[8] Outline drawings were produced by Woolwich Arsenal based on the A12 Matilda turret – the Director of Mechanisation opposed a turretless design – and the engine and Wilson epicyclic transmission being developed for the A13 Mark III Covenanter tank.

[14] Although using sidevalves to fit within the space, the engine was developed with high squish pistons, dual ignition and sodium-cooled exhaust valves in Stellite seats to give 350 bhp.

[15] With a German invasion of Britain looking imminent, and the loss of a substantial amount of military vehicles in the evacuation from France, the War Office specified that the A22 had to enter production within a year.

All those things which we know are not as they should be will be put right.Harold Drew of Vauxhall achieved miracles with the Churchill and its Merrit-Brown Tank Gearbox produced by David Brown Limited; "a brilliant design that went into production off the drawing board without adequate prototype testing and had the most disastrous teething troubles" according to Robotham,[citation needed] but British tanks were under-powered, under-gunned and unreliable.

[18] The poor speed of the Churchill nearly caused production to be ceased in favour of the forthcoming Cromwell tank; it was saved by the successful use of the Mk III at the Second Battle of El Alamein in October 1942.

Due to the number of wheels, the tank could survive losing several without much in the way of adverse effects as well as traversing steeper terrain obstacles.

With the introduction of the Churchill Mk vii and viii, the engine was uprated to 350 bhp (260 kW) at 2,200 rpm, presumably to counteract the increased weight.

[22] The first turrets were of cast construction and were rounded in shape, providing sufficient space to accommodate the relatively small 2 pounder gun.

To fulfil its role as an infantry support vehicle, the first models were equipped with a 3-inch howitzer in the hull[23] in a layout very similar to the French Char B1.

The tank underwent field modification in North Africa with several Churchills being fitted with the 75 mm gun of destroyed M4 Shermans.

The use of the 75mm increased despite its worse anti-tank performance when compared to the 6pdr due to the HE rounds used by the 75mm being considerably more effective when used in infantry support roles.

The sides, which included a flared base to protect the turret ring, were a single casting while the roof, which did not need to be so thick, was a plate fitted to the top.

By the war's end, the late model Churchill Mk VII had exceptional amounts of armour – considerably more than the German Tiger tank.

The Mark VII turret that was designed for the 75 mm gun was of composite construction – cast with top and bottom plates welded into position.

One action in Normandy where the tank's ability to surmount obstacles was found to be of value was the capture of Hill 309 on 30/31 July 1944 (Operation Bluecoat) conducted by VIII Corps.

Together with Broom & Wade (at High Wycombe) they started rebuilding earlier tanks; about 700 of the first 1,000 built were included in this scheme.

The beach was chert which included larger stones than the anticipated shingle: according to history professor Hugh Henry, the German defenders had previously considered it impassable to tanks.

[36] These surviving tank crews fought to cover the withdrawal of the infantry from the beach, and almost all were captured with their vehicles, having exhausted their main gun ammunition.

[37] Two Mark II had been sent to North Africa for trials and they were joined by six Mk III Churchills (with the 6 pounder) to form the Special Tank Squadron commanded by Major Norris King.

[40][41] Kingforce, formed to test whether the Churchills could operate in Africa, was considered too slow to participate in the chase after the retreating Axis, sent back to Alexandria and disbanded after El Alamein.

The Churchill was able to cross the muddy ground and force through the forests of the Reichswald; a contemporary report expressed the belief that no other tank could have managed the same conditions.

Although a small number of tanks were delivered, and some training undertaken, the end of the war against Japan meant that the conversion was not completed.

To restore the 1st Battalion, Royal Northumberland Fusiliers' position during the defence of Seoul, Brigadier Thomas Brodie of the 29th Infantry Brigade sent four Churchill tanks as reinforcement; their contributions to the battle were widely praised by British and American historians.

[56] Soviet operators disliked the 2 pdr gun of the Mk II version (also used by Matildas and Valentines shipped to the USSR),[56] and the tank was considered "sufficient" by inspectors, who warned that it was "unrefined" in terms of both design and production and would require constant maintenance in the field.

The test programme was completed but the project was cancelled due to the success of the new and less complicated Centurion Mark I, which offered the same armament and frontal armour, was faster and more manoeuvrable, and had just entered production.

After the Black Prince, no more Churchills were developed, as the army had shifted in favour of the above-mentioned Centurion, which was mainly claimed as the first Main battle tank, and also, the British army was going through a change of doctrine, meaning large infantry tanks to support men were no longer needed on the front.