The Churchill Mk IV NA75 was produced in North Africa by fitting 75mm guns from Sherman tanks into the cast turrets of the Churchill Mk IV.
During the fighting around Kairouan in Tunisia forty-eight Shermans ran into a minefield and suffered too much damage to be worth repairing. When they were being scrapped Captain Percy Morrell of the REME realised that most of their 75mm guns were still in working order and decide to try and fit the American gun in the cast turret of the Churchill Mk IV.
The standard Churchill IV had an internal gun mantlet, which was unpopular with its users. Morrell adapted the American full width eternal mantlet for the NA 75. He also had to alter the internal shape of the turret to make space for the bigger gun. The breech of the 75mm gun had to be rotated through 180 degrees to put in on the correct side for the crew layout of the Churchill. The Sherman used a periscope gun-sight, and so this had to be installed in the Churchill turret roof. The NA 75 used Browning machine guns in the turret and in the hull front.
Work on large scale production of the NA75 was carried out 16 Base Workshops, near Bone in Alegira and by June 1944 around 200 had been produced. British 75mm-armed Churchills were largely committed to the fighting in northern Europe, and so the NA75 was an important bonus for the troops fighting in Italy.
The Mk IV NA75 could carry 84 rounds of 75mm ammo, exactly the same as the 84 rounds of 6-pounder ammo carried in a standard Mk IV.
The Churchill Mk IV NA75 went to Italy in the Spring of 1944 with the 21st Army Tank Brigade. They performed well in the fighting in Apennines after the fall of Rome, where their ability to turn while standing still and excellent climbing ability allowed them to cope with the difficult terrain. A shortage of tanks meant that they had to operate alongside Shermans, so the thick-armoured Churchills were used to break through German defences, and the faster Shermans to exploit any gaps that were created. The Mk IV NA remained in service in Italy until the end of the war in 1945.
Morrell was rewarded for his efforts with the award of the M.B.E. and promotion to Major.