In 1924 the former Vickers Light Tank Mk I was redesignated the Medium Tank Mk I. The Mark I Medium Tank was the first tank designed after World War I.
The Medium Tank Mk I was constructed by riveting armored plates together.
The engine was placed at the front of the Medium Tank Mk I, next to the driver. Between them was a double asbestos and steel partition.
The Mk IA had plates that folded back.
The engine used steel cylinders with aluminum casings. Air was drawn over oil cooling pipes to cool the engine. There was 13 1/2 gallons of oil used throughout the engine. The Mk I's engine had to be started from the inside.
The engines were notoriously hard to start up and in one instance after a severe frost it took six hours to start three tanks.
The Mk IA had an access opening that allowed for the engine to be started from outside the tank.
The Mark I Medium Tank was the first British tank to have a turret.
The turret of the Mk IA* had a counterweight installed to balance the command post that was installed, also known as the "Bishop's Mitre." The gunner didn't have a seat and had to coordinate his right hand, working in the horizontal, with his left, working in the vertical.