Beretta 1010 Machine Pistol

Beretta 1010 Machine Pistol is machine pistol. This model is a highly compact machine pistol designed for undercover security work and protect ion duties. In its basic form, the Beretta is somewhat inaccurate, but with the addition of either a laser or smart-rig it becomes ideal for its chosen role. Compact and thin, it produces no unsightly bulge in your designer suit when you're out escorting your employer. For further compactness a smaller magazine can be fitted (15 rounds) and the barrel shroud removed. This has the effect of lowering concealability to a large pocket: rating P (how large a pocket, the referee can decide).

Source

 * Rough Guide to the UK, pg.38
 * Blackhand's Street Weapons, pg.18