Based on an experimental "India Pattern" design by Vickers in 1933.
The turret was positioned more towards the rear than previous Light Tanks. The turret was rounder that previous models. The turret had L shaped clamps that kept it from coming off. The turret rode on nine ball bearing rollers.
A brake had to be released first and then each turn of the traverse wheel moved the turret 5°.
There was a box that was located at the bottom of the tank that did move with the turret that housed the radio's batteries.
The Light Tank Mk IV was the first to have the hull used as a chassis that had components attached. This provided a more rigid body. This was the first British tank to have the hull extending over the tracks.
There was no rear idler on the Light Tank Mk IV. A Horstmann suspension with two springs on each side of the bogies was used.