In 1940 several commities were formed to look at forms of body armour for the troops including helmets.The Mk.11 helmet was originally designed to protect troops in trenches against falling shrapnel, but trenches and that form of explosive were no longer in general use. Were as greater protection against horizontal moving missiles would be better, it was decided to investigate the possibility of altering the shape of existing mk.11 helmets, several examples were made but it was found to be impractical. So in December 1940 it was decided that a totally new pattern of helmet should be designed, a sub commitee was formed including medical personel to decide on the shape of the new helmet. In April 1941 it was recommended to the war office that the new shape of helmet should be considered for troop trials, on the 3rd of July the army council accepted their report and ordered that 500 helmets were to be made for evaluation in the field. The new helmet was designated 'helmet steel mk .111 , the evaluations were favourable except for the resemblance to foreign helmets. By this time the Americans had come into the war so the American M.1 came under inspection of medical personel and they decided it gave better protection than ether the Mk.11 or mk .111 helmets, the M.1 was reviewed by the sub commitee and it was decided that the American steel helmet had certain disadvantages two of the main ones were it was not compatible with the type of headphone equipment used by the British also the anti gas helmet curtain. The Americans were not willing to alter their helmet to meet British requirements, and at the time it was not feasible to make the helmet in Britain, it was there for decided in February 1943 to abandon the idea of having the American helmet, and to put the mk.111 into production which started in November 1943, the introduction of the Mk.111 into the army was done gradually on a maintenance basis. the Main exception to this was the assault formations of 21 Army group who were almost totally re-equipped with the Mk.111 for the Normandy landings. The liner used in the Mk.111 helmet is a slightly modified standard Mk.11 liner, the modifications were needed because of the size difference between the Mk.11 and Mk.111 helmets, the modifications are the rubber buffers of the lining were in a different configuration and were of a different thickness.The liner pictured is a post war replacement and in poor condition. The chinstrap is a Mk.111, introduced in march 1941 the mk.111 is made of 25.5mm wide elasticised webbing and attached to the helmet at one end by a brass loop, at the other end is a tongueless buckle for adjustment and attachment to the other chin strap lug.