The above photograph of Winston Churchill with the Thompson submachine gun was taken during his visit to the coastal defense positions near Hartlepool on 31 July, 1940.
The British Army, more notably the B.E.F - British Expeditionary Force were apparently the first to utilize the Tommy gun in WWII combat. Later on issued with several 30 round box magazines as the drum magazines were too bulky for an infantryman to a carry.