The Viennese Connection: Engelbert Broda, Alan Nunn May and Atomic Espionage

Recently declassified materials have revealed the existence of a previously unknown network of Austrian communists in pre-war England. The group of young well-educated Viennese used unsuspecting social contacts and marriages of convenience to establish itself. Analysis of this network reveals some previously overlooked similarities between the 'Cambridge' spies Kim Philby and Alan Nunn May, as well as the emergence of a new nuclear spy, Engelbert Broda. Their wartime espionage as individuals took place at a time when non-communist British scientists were promoting the international sharing of atomic knowledge through unofficial channels. The newly released files reflect a characteristic preference of the British secret services for intelligence gathering rather than intervention and illustrate how vital leads follow from apparently trivial observations.