In Great Britain were in the 1930's the thought's, that a next world war would be more or less the same as the Great War of 1914/'18. The best way to protect the infantry was a heavy armoured vehicle. The tank would have to be able to climb steep hills and maneuver through rough terrain. Because it was to support the infantry, a great speed was unnecessary. Harland & Wolff were given the task to develop four prototypes under specification A20. The first one had to be ready by June, 1940 for testing.

During the testing it was clear that the basis of the tank was good, but it was unreliable. The tank was designated to get a 2 pouder gun, a gun that was by that time already to weak for it's purpose.

After the evacuation of Dunkirk, the British had only a 100 tanks left to protect the country. Vauxhall was given the order to produce an updated A20, preferable within the year. Vauxhall was chosen because of the engine, the Vauxhall-Bedford was picked as power source for the A20. In November 1940, the first updated prototype, the A22 Tank IV, emerged from the factory.

Of an order of 500 A22's, the first 14 were delivered in June, 1941. Because of the fast production, the first tanks were troubled with a lot of malfunctions. During the years 1942-1943 the concept was constantly adapted and upgraded. Under supervision of Vauxhall, several companies worked on the A22, now called the Churchill. The production force consisted, beside Vauxhall, of Broom & Wade, Birmingham Carriage & Wagon, Metropolitan Cammel, Charles Roberts, Newton Chambers, Cloucester Railway Carriage, Leyland, Dennis and Harland & Wolff.

The 2-pounder gun in the turret of Infantry Tank Mk IV, Churchill Mk I lacked a HE (high explosive) grenade. To support the 2-pdr, a 3 inch howitzer was placed inside the hull, left of the driver

The bad vision that was created because of the far protruding tracks in front of the tank, and the limited movement of the howitzer in it's low position, the gun was virtually useless. The dead useless weight of the howitzer was replaced with a 7.92 caliber Besa machinegun, creating the Churchill Mk II. The turret was also given a mechanism to launch smoke grenades.

During March 1942 the first Churchill Mk III's were produced. The 2-pdr gun was replaced by the much more effective 6-pounder gun. The turret was completely redesigned and was built up from plates in stead of the cast one of her predecessors. But the armoured plating became difficult to come by in wartime, so a new cast turret was developed, creating the Churchill Mk IV, the most produced version of the Churchill. The first versions of the Mk IV's, with the 6-pdr, that were produced had a weight at the end of the barrel for balance. For the 6-pdr was a HE grenade available, but because of the small caliber (57mm) not yet to great effect.

The first action for the Churchill came on August 19, 1942 during the failed Dieppe Raid. Thirty Churchill's Mk I's, Mk II's en Mk III's were deployed, but not a single Churchill made an impression. The beach, mainly pebbles, made maneuvering difficult. Important lessons were learned from this landing.
Six Mk III were shipped tot Africa. These were put to action during the battle of El Alamein, October 1942. The First Army was later equipped with 120 Mk IV's, from which a lot of them had their 6-pdr replaced by guns from M4 Sherman tanks that were put out of action.

The standard Mk IV Churchill was not the end of the development. The armour became heavier and details changed, like the square hatches at the side, which were made round. Also the hatch in front of the driver was made round. Despite the increase in weight (over 40 tons), the power source stayed the Bedford 'Twin Six' 12 cylinder engine. The 350 HP gave the tank a speed of around 25 km/h.

In 1943 the Churchill got a new cannon, the British version of the 75mm. It could now use the American HE ammunition. This version became known as the Mk VII. Despite all these changes, a lot of Mk IV's stayed in frontline with their 6-pdr.