In September 1942, the Director of Naval Intelligence authorised the formation of the Special Intelligence Unit, composed of 33 (Royal Marines) Troop, 34 (Army) Troop, 35 (Royal Air Force) Troop and 36 (Royal Navy) Troop.
The unit was initially deployed for the first time during the Dieppe Raid in August 1942 in an unsuccessful secret attempt to capture an Enigma machine and related materials,[REF] and then took part in the Operation Torch landings in November 1942.