The file claimed that Hitler was “convinced that Great Britain is ‘decadent’ and lacks the will power to defend the British Empire” and added: “If the information in the [report] which has proved generally reliable in the past, is to be believed, Germany is at the beginning of a ‘Napoleonic era’ and her rulers contemplate a great extension of German power.”

At the suggestion of one officer they included samples of Hitler’s insulting references to Chamberlain which was said to have had “a considerable impression on the Prime Minister.”

Lord Halifax, the Foreign Secretary, underlined three times in red pencil Hitler’s reported description of Chamberlain as an “arschloch” before handing it on to the Prime Minister.