text: It has been said that the main value of the convoys was political, proving that the Allies were committed to helping the Soviet Union at a time when they were unable to open a second front.
  British intelligence
  Ultra signals intelligence gained from the German Enigma code being broken at Bletchley Park played an important part in the eventual success of the convoys. German documents related to the Enigma coding machine were captured during the commando raids of Operation Archery and Operation Anklet (27 December 1941). The documents enabled the British to read messages on the home waters naval Enigma used by surface ships and U-boats in the Arctic (Heimisch, later Hydra network; Dolphin to the British) for the rest of the war. In January 1942 reinforcements of Luftwaffe bombers, torpedo-bombers and long range reconnaissance aircraft were sent to northern Norway and new command organisations established at Stavanger and Kirkenes, followed by Fliegerführer Lofoten who was charged with the defence of Norway and offensive operations against Allied convoys. The three U-boats in the area were increased to nine and another six were distributed between Bergen, Trondheim and Narvik to reconnoitre and oppose Allied landings. In May, all the U-boats came under Arctic Command and on 23 May, Admiral Scheer and Prinz Eugen joined Tirpitz at Trondheim, followed by Admiral Hipper; by 26 May Lützow had arrived at Narvik.