Designed around an adapted MkIII Lee-Enfield action and stock the De Lisle is chambered in .45ACP, accepting slightly modified .45 calibre Colt 1911 pistol magazines rather than Lee Enfield’s usual 10-round .303 magazine. The key element of the De Lisle’s design was the 21 cm long integral barrel sound suppressor (silencer). The suppressor allowed propellent gas from the rifles .45 cartridge to bleed out of the barrel quietening the sound of the round leaving the muzzle.
The weapon was developed by engineer William Godfray de Lisle & Major Sir Malcolm Campbell of the office of Combined Operations (later famous for his land and water speed records). The carbine was originally chambered in .22 but when De Lisle offered the carbine to the Allied Combined Operations a 9mm version was requested. The 9mm prototype however was a failure due to the light weight and high velocity of the round. The carbine was then rechambered to accept .45 ACP and was found to be extremely quiet due to the round’s lower velocity and the carbine’s suppressed barrel.
The prototype development was completed by 1942 and was followed by a production run at the Sterling Armaments Company, later known for their submachine gun, with around 150 being built throughout the war with a later model featuring a folding metal stock. Sterling also developed a version with a folding stock intended to be more compact for possible use by paratroops. However, only two of these paratroop De Lisle’s were produced.
De Lisle carbine with folding metal stock (source)
It was issued to British Commando units and the SOE (Special Operations Executive) during World War Two. Accurate at up to 200 yards, with no muzzle flash and extremely quiet they used to kill sentries during infiltration missions. They were used by Commandos and the SOE in Europe and several found their way to Allied forces in Burma. Following the end of the war they remained in service until the 1960s with De Lisle’s finding use during the Korean War, the Malayan Emergency (see image #3) and possibly during The Troubles in Northern Ireland. They’re much less well known than the other silenced weapons of the war; the Welrod pistol or the silenced STEN submachine guns (MkII & VI).
The secret story of two sisters who risked their lives to transmit messages from within Occupied France during the final years of the war is finally published, two years after agent Didi Nearnes died at home in Torquay.