For the last four gruelling years of the war, the Western Allies supplied arms and ammunition to Soviet Russia, essential to the Russian war effort. Allied merchant ships ran the gauntlet of the icy Barents Sea, outflanked by German bases in Norway, from where bombers, surface warships and U-boats could attack without warning. Each delivery of arms was an epic achievement; an eminent British historian described it as undertaking the impossible. Under pressure from both Stalin and Roosevelt, Churchill compelled the hardpressed British navy to fight convoy after convoy through to Murmansk and Archangel, with considerable loss. It was the Arctic that saw the last concentration of the U-boats; the Arctic that saw the last Royal Naval ship sunk in European waters; and the Arctic that saw the greatest defeat of a convoy in modern history. It was a theatre dominated by the weather: fog, storm-force winds and the ever-present numbing cold; and accretions of ice caused ships to capsize.The debacle of PQ17, the surface actions, the U-boat attacks and running air battles culminating in the final destruction of the Scharnhorst are fully covered, but so too are the personal angle and the perspective of the long-suffering merchant ships and their crews, together with the political implications.