THE WAR BENEATH THE WAVES

The sinking of HMS Royal Oak 86 years ago, just six weeks into the Second World War, sent shockwaves through Britain. And as a thrilling new account of the U-boats reveals, this opening salvo of the undersea battle served to stoke fears of maritime vulnerability

- By Roger Moorhouse

N the chill early hours of October 14, 1939, the heavy shape of HMS Royal Oak lay quietly at anchor in Scapa Flow. The Orkney anchorage, bastion of the Royal Navy since the Great War, was supposed to be impregnable — a natural fortress guarded by booms, blockships and the sheer distance from enemy waters.

Yet at 12:58am, a dull thud reverberated through the Royal Oak’s hull. Men stirred in their hammocks while those on watch muttered about a minor internal explosion. Eighteen minutes later, three more torpedoes struck home amidships. The deck lights flickered, bulkheads buckled and the great ship began to list. Within a quarter of an hour, she rolled over and disappeared beneath the black water, taking 835 men with her.

The attacker, U-47, commanded by Kapitänleutnant Günther Prien, slipped back through the narrow channels of Kirk Sound and into the North Sea, unchallenged.

When the news broke the following morning, Britain was aghast. The Times called it “an outrage” and lamented that “command of the sea is not lightly won”. For a nation barely six weeks into a new war, the sinking was a profound shock: if a German sub could creep into Scapa Flow and destroy a battleship at anchor, surely nowhere was safe?

The Royal Oak disaster became, almost overnight, a symbol of British vulnerability. Winston Churchill — then First Lord of the Admiralty — was deeply shaken. Like so many of his generation, he was haunted by memories of 1917, when German submarines had come perilously close to starving Britain into submission.

The assumption, widely shared at home and abroad, was that history was about to repeat itself on an even greater scale.