US intelligence errors helped build myth of Nazi Alpine redoubt, says historian

New book claims intercepted cables sent in second world war by Allen Dulles, later head of CIA, enabled disinformation campaign

A US spymaster inadvertently helped the Nazis develop one of the most effective disinformation campaigns of the second world war by spreading rumours about Hitler's plans for a Where Eagles Dare-style Alpine redoubt, a historian with access to classified US military records has found.

The myth that the Nazis were amassing weapons and crack units of 100,000 fanatical soldiers in the spring of 1945 for a last stand in the Austro-Bavarian Alps was without any basis in fact but had a powerful hold on the imagination of American and British military leaders, who feared it could prolong the war for years.