The Allied invasion of mainland Italy in the Second World War, which began on the morning of 9 September 1943 with a landing on the beaches of Salerno, south of Naples, was the largest amphibious operation before D-day. Although there was stiff German resistance, Italian guns, save for those of a few diehard Fascists, were silent. The complex, secret negotiations for an Italian surrender after the overthrow of Mussolini almost six weeks earlier had already begun in earnest with the arrival of an Italian delegation in neutral Madrid on 15 August to meet the British ambassador, Sir Samuel Hoare.

Hoare’s intelligence background and previous dealings with Mussolini, which help to provide the context for his role in the summer of 1943, are not mentioned by Roderick Bailey. While chief of the MI5 wartime mission in Italy during the final year of the First World War, Hoare, previously head of