Yet another book on the origins of the Second World War might seem excessive, but this one takes an original approach. Its focus is on the quality and accuracy of information obtained through espionage during the interwar period, especially among the main powers, and how far failures of intelligence contributed to the war.

Underlying all this was the mercurial nature of Hitler’s leadership and the inherent difficulty of anticipating either his next move or his ultimate foreign policy aims. The argument of this book is that the Western Allies turned a blind eye to Nazi Germany’s secret rearmament from 1933, in defiance of the major restraints on it imposed through the Treaty of Versailles in 1919, and then, in 1938, much overestimated Hitler’s military might. Having avoided military intervention early on to contain Nazi Germany, they also shirked a military showdown in defence of Czechoslovakia in 1938 before taking up arms following Hitler’s invasion of Poland a year later, by which time the German war machine was much better prepared.

A lot of this is familiar ground. What’s original is the discussion of the often poor and contradictory quality of Anglo-French intelligence and Germany’s success at duping its rivals. Parts of this book read like an exciting cloak-and-dagger story revolving around the exploits of various military attachés, professional spooks