On the 27th of July 1942 convoy PQ-17 departed Iceland for the Soviet Union. Out of 34 merchant ships, only 11 would make it to port. At first, things seemed to be going well for the convoy as they beat off multiple German air attacks with relative ease. But on the 4th of July, everything went wrong. An order arrived from Admiral Sir Dudley Pound, the First Sea Lord himself reading 'Convoy is to scatter'. Fearing an imminent attack from German surface ships like Tirpitz the escort ships fled west while the merchant ships made for the Soviet Union.

But the Tirpitz was nowhere near the convoy, in fact, it was still at its moorings in northern Norway. Instead of saving the convoy from disaster, Admiral Pound's order had doomed PQ-17 to destruction. Over the following week, two-thirds of the convoy were sunk by German aircraft and U-Boats. It was the biggest loss to a single British convoy in the Second World War.

In this video, IWM's Rob Rumble joins us from HMS Belfast in an attempt to uncover what went wrong. Why did Admiral Pound give the order to scatter? What was it like for the sailors and U-Boat crews? And how did the disaster of convoy PQ-17 affect the outcome of the Second World War?

A 5-minute history of the Arctic Convoys: https://www.iwm.org.uk/history/a-5-minute-history-of-arctic-convoys

HMS Belfast and the Arctic Convoys: https://www.iwm.org.uk/history/hms-belfast-and-the-arctic-convoys

Licence the clips used in this film: https://film.iwmcollections.org.uk/c/2595

For information about licensing HD clips please email filmcommercial@iwm.org.uk