On 10 May 1941, on a whim, Hitler's deputy Rudolf Hess flew a Messerschmitt Bf 110 to Scotland in a bizarre effort to make peace with Britain; Göring sent fighters to stop him but he was long gone. Imprisoned and tried at Nuremberg, he would die by his own hand in 1987, aged 93. That's the accepted explanation. Ever since, conspiracy theories have swirled around the famous mission. How strong were Hess's connections with the British establishment,...