MCEM-2 (Machine Carbine Experimental Model 2) submachine gun was produced only in prototype form, but it is worth to mention by the simple fact that it is one of the very first submachine guns to combine wrap-around bolt and magazine in pistol grip - features, later copied in Czechoslovak SA.23, Israeli UZI and a great number of other submachine guns. MCEM-2 was the second prototype in a line of experimental submachine guns, designed in Britain in 1944. It was envisioned as a possible replacement for the STEN submachine gun then in service. The MCEM-2 was developed by polish immigrant, someone called Podsenkowski. It is believed that prototypes of MCEM-2 were made before the end of WW2, and its derivatives MCEM-4 and MCEM-6 were tested soon after the war. The latter modifications differed mostly in adoption of the rate-reducing mechanism, incorporated into trigger unit; the rate of fire therefore was decreased from 1000 to more realistic 700 rounds per minute. Nevertheless, neither prototype was found suitable for adoption, and several years later British army adopted a more conventional submachine gun, the Sterling-Patchett.
MCEM-2 is blowback-operated, selective fired weapon which fires from open bolt. The bolt is of "telescoped", or "wrap-around" type, with most of its mass being in front of the breech face. The receiver is made from steel tube, and pistol grip with trigger unit is attached below. magazine is inserted into the pistol grip. safety and fire mode selector are incorporated into one three-position switch, located in front of the trigger on the left side of the trigger unit housing. The guns was developed along with large semi-rigid holster, which can be attached to the receiver of the gun to form the shoulder stock.