The convoys demonstrated the Allies' commitment to helping the Soviet Union, prior to the opening of a second front, and tied up a substantial part of Germany's naval and air forces.

[2] During World War I (1914–1918), Central Powers blockades halted traffic between Imperial Russia and its Allies via the Black Sea and the Baltic.

The Tsarist authorities sped up development of an ice-free port at Romanov-on-Murman (present-day Murmansk); however, supplies arriving via the Arctic came too little and too late to prevent the Allied collapse on the Eastern Front.

Britain was quick to provide materiel aid to the USSR beginning in August – including tanks and aircraft – in order to try to keep her new ally in the war against the Axis powers.

The USSR thereafter became one of the "Big Three" Allies of World War II along with Britain and, from December, the United States, fighting against the Axis Powers.

This, together with the obvious need to stop convoy supplies reaching the Soviet Union, caused him to direct that heavier ships, especially the battleship Tirpitz, be sent to Norway.

As the Allies closed the air gap over the North Atlantic with very long range aircraft, Huff-Duff (radio triangulation equipment) improved, airborne centimetric radar was introduced and convoys received escort carrier protection, the scope for commerce raiding diminished.

In particular, the unsuccessful attack on convoy JW-51B (the Battle of the Barents Sea), where a strong German naval force failed to defeat a British escort of cruisers and destroyers, infuriated Hitler and led to the strategic change from surface raiders to submarines.

Towards the end of the war the material significance of the supplies was probably not as great as the symbolic value hence the continuation—at Stalin's insistence—of these convoys long after the Soviets had turned the German land offensive.

[17] 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.

[2] 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.

The reinforcement of the U-boat force in the Arctic to 12 in March and 21 in August (the real number was later found to be 23) was followed, along with the transfer orders to the large German ships, leading to the ambush of Prinz Eugen by the submarine HMS Trident off Trondheim on 23 February.

[19] The information could not always be acted upon because much of it was obtained at short notice but the intelligence did allow the Royal Navy to prepare for battle and convoys could be given appropriate escorting forces.

[20] The 1955 novel HMS Ulysses by Scottish writer Alistair MacLean, and the 1967 novel The Captain by Dutch author Jan de Hartog, are set during the Arctic convoys.

From July through September small Soviet convoys assembled in Providence Bay, Siberia to be escorted north through the Bering Strait and west along the Northern Sea Route by icebreakers and Lend-Lease Admirable-class minesweepers.