Vickers A1E1 Independent

The Independent A1E1 is a multi-turreted tank that was designed by the British armaments manufacturer Vickers between the First and Second World Wars. Although it only ever reached the prototype stage it influenced many other tank designs.

The A1E1 design can be seen as a possible influence on the Soviet T-100 and T-28 tanks, the German Neubaufahrzeug tanks, and the British Medium Mk III and Cruiser Mk I (triple turret) tank designs. The Soviet T-35 tank was based extremely closely on its plans and layout.

Design
The Independent was a multi-turret design, having a central gun turret armed with the 3 pounder (47 mm) gun, and four subsidiary turrets each armed with a 0.303 inch Vickers machine gun. The subsidiary turrets were mounted two at the front and two to the rear of the turret (about halfway along the hull). The gun of the left rear turret was able to elevate to engage aircraft. The tank was designed to have heavy firepower, self-defence capability, and superiority to enemy weapons. It had a crew of eight men, the commander communicating with the crew through an intercom system. The Independent was never used in combat, but other armies copied it.

History
In 1924 the General Staff of the British Army ordered the prototype of a heavy tank, which became known as the Independent. Largely designed by Walter Gordon Wilson, its 35.8 litre V12 air-cooled engine was designed by Armstrong Siddeley, and it also incorporated a new hydraulic braking system which had to be specially developed due to its weight and speed. The prototype was delivered to the War Office in 1926, but was abandoned due to a lack of funds.

The tank was the subject of industrial and political espionage, the plans ending up in the Soviet Union, where they may have influenced the design of the T-28 and T-35 tanks. Norman Baillie-Stewart, a British military officer, was court-martialled in 1933 and served five years in prison for providing the plans of the Independent (among other secrets) to a German contact.

The Independent is preserved at the Bovington Tank Museum in the UK.