FOR AT least two years, Britons nervously watched the seas and skies of the English Channel for a Nazi invasion fleet that never came.

But remarkable, newly-released British secret service documents reveal that Hitler planned an invasion of an entirely different kind from the extreme north of Scotland.

Instead of ships, troops and tanks, the Nazi dictator wanted to introduce lethal bacteria to Shetland, from where they would spread death and panic across the British Isles.

The declassified documents show the amazing plot began in January 1943 when three exhausted Norwegians staggered ashore in Lerwick after a 46-hour journey across the North Sea from Nazi-occupied Norway.

Because the registration number of their fishing boat resembled that of a missing Special Operations Executive (SOE) vessel, the men received a VIP welcome. The boat was not searched and the men were taken south without having to answer any awkward questions.