Shortly after 11 pm on 10 May 1941, a Scottish ploughman spotted a parachutist floating to the ground in a field at Floors Farm, a dozen miles south of Glasgow. He ran out to find a burning twin-engine Messerschmitt Bf 110 bomber and an injured officer wearing the uniform of a captain of the German air force. The aviator identified himself as Captain Albert Horn and asked to be taken to see the Duke of Hamilton for whom, he claimed,...