GERMANY WAS DEVELOPING a plan to invade Ireland during the Second World War, using shock troops dressed in British army uniforms.

If the Luftwaffe had won the Battle of Britain, newly-released MI5 files suggest, German troops would have invaded Dover, Scotland and the south coast of Ireland.

Details of the plan, called Operation Sea Lion, have emerged in a post-war debrief of a German soldier from an MI5 file which has just been made public at the British National Archives.

Corporal Werner Janowski was interrogated about his wartime work for the German Intelligence Service, the Abwehr.

The plan was that a huge aerial bombardment would precede the attacks. Janowski told M15 how, after the shock troops had captured the docks at Dover, the main contingent of German troops would be brought over to Britain in barges and disembark at the docks.

But Hitler cancelled the invasion because Hermann Goering’s Luftwaffe had been unable to destroy the RAF. Without air superiority, he felt the German troops would have been too vulnerable.

The news that Hitler had designs on Ireland won’t come as any surprise to historians – since the 1940s, there has been speculation about such plans.

But Janowski’s testimony provides concrete evidence that Operation Sea Lion wasn’t simply postwar propaganda aimed at stirring up anti-German feeling.