From 1940 until 1942 the British Army and the Medical Research Council (MRC) worked hard at developing a set of body armour that could fill the needs of all three services had to be considered as well as designing a piece of equipment that could be worn comfortably.
The material used in this body armour was the same 1mm manganese steel found in British helmets. The body armour, weighing 3½ pounds, was designed so that its three pieces covered the vital parts of the body.