Arctic Convoy PQ17 was the victim of confusion, uncertainty and ambition by friend and foe. As a result, 153 seamen died, and more than 20 ships – representing almost 100,000 tons of cargo, more than 400 tanks, 210 aircraft and 3,300 other vehicles – were sent to the icy depths of the Arctic seas.

The doomed eastbound convoy – those travelling to Russia were prefixed PQ, those travelling west were QPs – gathered in the Icelandic port of Hvalfiord in late June 1942, the crews apprehensive but reassured by the promise of considerable escort force.

These were to include a close escort of six destroyers, four corvettes, three minesweepers, four armed trawlers and two ack-ack ships.

But the convoy was also to be screened by a force of four heavy cruisers – HMS London, HMS Norfolk, USS Tuscaloosa and USS Wichita – and three further covering destroyers.

And standing well off, spoiling for a fight, was a large part of Admiral Tovey’s Home Fleet, including the aircraft carrier HMS Victorious, battleships HMS Duke of York and USS Washington, two cruisers and eight destroyers.

This collection of major warships was not directly charged with protecting the convoy – instead, they were waiting for a sniff of the German battlegroup based on the battleship Tirpitz.

Tirpitz and her consorts had slipped northwards along the Norwegian coast, from where she and her consorts could wreak havoc on a convoy – or break out into the Atlantic to prowl with greater freedom.

Fears over what the mighty Tirpitz could do went to the highest levels of the wartime British government, and she was seen as a crucial factor in the war at sea.

Sinking her would be a major victory to the Allies – and Hitler was also aware of the consequences of such an action.

So Tirpitz had to be protected, and used sparingly when there was even the remotest of threats – and the threat provided by an Allied carrier group was far from remote.

As PQ17 chugged eastwards, with one ship already out of the group because of an accident on leaving Iceland, the cat-and-mouse manoeuvres between the two groups of heavy warships and their controllers began, egged on by the political strictures of Washington, London and Moscow, who needed to see weapons, equipment and supplies flowing to the Red Army on the Eastern Front.

RAF reconnaissance flights over the known berth of the Tirpitz reported that through breaks in the cloud they could see that their quarry had sailed, but her exact position was unknown.

This information rang alarm bells in the Admiralty, and as a result the Allied fleet was put on alert for a major engagement.

Meanwhile, German reconnaissance flights were giving the German hierarchy an equally incomplete picture; reports of a task group complete with carrier sowed the seeds of doubt, and other reports from German U-boats which were beginning to shadow Convoy PQ17 told of carrier-borne aircraft in the vicinity – a mistake possibly caused by the sighting of a cruiser’s Walrus seaplane.

At that point safety became paramount – the safety of the Tirpitz, and the safety of the Allied cruiser and destroyer force as a vital element of the proposed action – and on the orders of First Sea Lord Admiral of the Fleet Sir Dudley Pound, PQ17 was ordered to scatter and the ships to make their own way to the safety of a Russian port, chiefly Archangel or Murmansk.

It is widely believed that Pound’s decision – a course of action usually taken as a desperate last resort when a convoy was about to be overwhelmed by superior forces – was affected by the brain tumour which was possibly beginning to cloud his judgement, and would kill him before the end of the war.

The ships of PQ17 had already beaten back bombing raids from German airfields in northern Norway, and U-boats were foiled by a combination of clear weather and calm seas, in which they presented easy targets for guns and depth charges, to say nothing of the diligence of the escorting anti-submarine ships.

But with the withdrawal of the cruisers and the screening destroyers, the gathered ‘ice devil’ U-boats were able to shadow the convoy with a great deal more ease, beaming homing signals to other submarines as well as large formations of bombers.

The convoy, still with the smallest escorts (corvettes, armed trawlers and AA ships) split into several groups, and began to spread out seeking the protection of bleak islands or the pack-ice to the north, with the mass of Novaya Zemlaya being the most immediate achievable landfall.

But the stragglers were quickly mopped up, as wave upon wave of bombers and prowling submarines picked them off. The German efforts were unrelenting, as they were looking for a major coup – and PQ17 was the prize.

Ironically, the big German ships never showed up. They were only hours out of Altenfjord when they were recalled, the German Navy unwilling to risk their heavy forces.

And the Allied groups, battleships, cruisers and destroyers, had sped away from the convoy, making it impossible for them to rejoin it – even if they had remained together.

The total destruction of PQ17 was only prevented by the ingenuity and resolve of some of the masters and their crews, and the efforts of the remaining escorts.

With ships that were beached along the way, or abandoned to their fate in mid-ocean, less than a third of the starters actually made it through to the safety of a Russian port.

The fate of PQ17 had far-reaching effects. The need to keep the Soviets supplied was overridden by the need to avoid another disaster on the scale of the convoy, described by Sir Winston Churchill as “one of the most melancholy naval episodes in the whole of the war.”

Summer runs were deemed too risky, because foul winter weather provided far better cover for slow-moving merchant ships.

PQ17 also made an unanswerable case for proper air cover – the doomed convoy had just a catapult-launched Hurricane to rely on.

With escort carriers alongside, the threat of attacks by bombers would be reduced, and the chances of survival of a U-boat sitting on the surface, waiting for its prey to hove into view, would have been as bleak as the chances of the near-defenceless freighters of PQ17.