The Medium Tank A7 was developed at the same time as the Vickers A6 and Medium Tank Mk III, but was produced 'in-house', with the design being led by the Chief Superintendent of Design.
Three prototypes were produced. The A7E1 and A7E2 were built in 1929-1931 and were very similar vehicles. The A7E3 was developed and built between 1933 and 1937 and was a modified model.
The basic layout of all three was similar. The hull was flat topped, while the turret was rectangular, with sloped sides and a commander's cupola. Unlike the Vickers designs the A7 didn't carry auxiliary machine gun turrets. The first two prototypes were powered by an Armstrong Siddeley engine. Although the basic design was good, the prototypes were unreliable.
The third prototype was heavier, better armoured and used two bus engines, giving it more power than the first two. Its design incorporated lessons learnt during work on the A6 and Medium Mk III, but as with the earlier prototypes it proved to be mechanically unreliable.
Although the A7 didn't enter production it was quite an influential design, providing elements that were used in the A9 Cruiser Tank Mk I, the A12 Matilda Infantry Tank, the Valentine, the A14 and the A17. The influence on the Matilda was most important as the prototypes were used as test beds for that design.
Stats (A7E1 and A7E2)
Weight: 14 tons
Engine: 120hp air-cooled Armstrong-Siddeley engine
Max Speed: 25mph
Armament: One 3pdr gun and two .303in Vickers machine guns
Hull Length: 22ft 6in
Hull Width: 8ft 11.5in
Height: 9ft 1in
Weight: 18.2 tons
Engine: Twin 252hp A.E.C. CI Diesel engines
Max Speed: 25mph
Armament: One 3pdt QF gun and two .303in Vickers machine guns