After Germany invaded the Soviet Union on 22 June 1941, the Soviet leader, Joseph Stalin, demanded help and Britain and its allies provided supplies. The most direct route was by sea, around northern Norway to the Soviet ports of Murmansk and Archangel. The route passed through a narrow funnel between the Arctic ice pack and German bases in Norway, and was very dangerous, especially in winter when the ice came further south. Many of the convoys were attacked by German submarines, aircraft and warships. Convoy PQ17 was almost destroyed.
The first convoy sailed in September 1941. The convoys were coded depending on their route - initially PQ for outbound, QP for homebound. From 1943, the codes changed to JW and RA - outbound and homebound respectively.