Chapter Five studies Ministerial reactions to the spy scandals that threatened Anglo-American nuclear exchanges. Considering the cases of Alan Nunn May, Klaus Fuchs, Bruno Pontecorvo, Guy Burgess and Donald Maclean, it argues that Ministers were sensitive to claims from the United States that Britain was weak in the field of security. After the Fuchs and Pontecorvo scandals, Ministers reacted quickly to repair any damage to transatlantic relations by introducing new security procedures known as ‘Positive Vetting’. The chapter also uses newly released archival material to shed light on Ministerial reactions to the disapperance of the Foreign Office diplomats, Guy Burgess and Donald Maclean, in the spring of 1951. Their defection provoked widespread outrage and, once again, prompted a review of security in government, on this occasion the Foreign Office, on the instructions of the Foreign Secretary, Herbert Morrison, now Foreign Secretary, which is explored here for the first time.
