A decisive intelligence failure? British intelligence on Soviet war potential and the 1939 Anglo-French-Soviet alliance that never was

In 1939 the British Government tried to assess Soviet war potential in order to know more about their potential ally, as part of the negotiations concerning an Anglo-French-Soviet alliance. British assessments of Soviet economic and military strength (and the internal stability of the Stalin regime) in this context have partly been neglected in earlier research, and it seems both that British estimates were much more off the mark than earlier supposed, and that the gross underestimation of Soviet strength in 1939 was probably a major factor in the British reluctance to enter into an anti-Hitler coalition with the USSR.<p>