Juan Pujol García, code-named GARBO by British MI5 and ARABEL by the German Abwehr, was the Spanish ‘double-cross agent’ who won both an MBE from the British and an Iron Cross from the Germans. The British knew the spy network of 27 subagents he ran was wholly fictional; German intelligence believed them real and trusted their information entirely. This meant that his message of 9 June 1944 suggesting the Normandy landings were a feint and the real attack was coming against the Pas de Calais persuaded Adolf Hitler to hold back his reserves for several weeks. Thus Pujol became the ‘spy who saved D-day’.

Pujol’s second great claim to fame is that he helped to open the door of official secrecy about the Second World War. In 1971, the legendary Daily Express journalist Sefton Delmer published the first book about Pujol, The Counterfeit Spy. Delmer changed facts and names to protect Pujol, disguising him as a Basque called Jorge