HMS Triumph (N18) was a T-class submarine of the Royal Navy. She was laid down by Vickers at Barrow-in-Furness and launched in 1938. The boat was lost in transit in 1942, with a crew of 64, and its fate was unknown until the sunken boat was rediscovered in June 2023.

Operation Colossus was the codename given to the first airborne operation undertaken by the British military, which occurred on 10 February 1941 during World War II. The British airborne establishment was formed in June 1940 by the order of the British Prime Minister, Winston Churchill, in response to the successful airborne operations conducted by the German military during the Battle of France. Training began immediately but a shortage of proper equipment and training facilities, as well as bureaucratic difficulties, meant that only a small number of volunteers could immediately be trained as parachute troops. The first airborne unit to be formed was actually a re-trained Commando unit, No. 2 Commando, which was subsequently renamed as No. 11 Special Air Service Battalion and numbered approximately 350 officers and other ranks by September 1940. The battalion finished its training in December 1940 and in February 1941 thirty-eight members of the battalion, known as X Troop, were selected to conduct an airborne operation, which was intended to test the capability of the airborne troops and their equipment, as well as the ability of the Royal Air Force to accurately deliver them.