Detail of centrefire self-loading submachine gun, Thompson model 1921A, about 1923, PR.7398. Royal Armouries, CC BY 4.0
Thompson submachine gun (PR.7398)
Designed at the end of the First World War by John T. Thompson, an American colonel who wanted to devise a gun that would sweep away the enemy from the trenches - a "trench broom". However, production of the prototype for his design was delayed until 1919, by which time the war was over and in peacetime there was no clear reason for a government to be interested in buying it. Instead, the gun was sold commercially. It had notable appeal to law enforcement and criminals alike, and was famously used by US gangsters as well as the Irish Republic Army (IRA) –this piece is one of 500 Thompsons ordered by the IRA. The gun was used until 1997, first belonging to the IRA, then the Provisional IRA, and the British Ministry of Defence, before coming to the Royal Armouries.