in the trade unions had been recruited long ago as Soviet agents. After the Soviet spy Kim Philby's defection to the USSR in 1963, following what Wright refers to as a warning by "a fifth man, still inside", he became convinced that the KGB had penetrated the highest levels of MI5. As claimed in Spycatcher, Wright had come to believe that Roger Hollis was the highest traitor in MI5. Wright went so far as to begin to make, as he himself put it, "his own 'freelance' inquiries into Hollis's background" shortly before the latter's retirement. According to Wright, his initial, unspecified suspicion was aroused by his analysis of the KGB's reaction to the arrest of a Soviet operative, Gordon Lonsdale, in January 1961. The KGB appeared to have had foreknowledge of the arrest, and Wright deduced that Lonsdale may have been sacrificed to protect a more important Soviet spy in Britain. Wright's suspicions were further strengthened by Hollis's apparent obstruction of any attempt to investigate information from several defectors that there was a mole in MI5; and he then discovered that Hollis had concealed relationships with a number of suspicious persons, including his longstanding friendship with Claud Cockburn, a communist journalist who was at the time suspected of connections to Soviet intelligence; and an acquaintance with Agnes Smedley while Hollis was serving in Shanghai, at a time when Smedley was in a relationship with Richard Sorge, a proven Soviet spymaster. Later during his investigations, Wright examined the debriefings of the Soviet defector Igor Gouzenko, and found to his surprise that the revelations of that debriefing were neither reported nor recorded. After a lengthy check, he discovered that it had been Hollis who was sent to Canada to interview Gouzenko. Gouzenko had provided Hollis with clear information about Alan Nunn May's meetings with his Soviet handlers. Gouzenko also noted that the man who met him seemed to be in disguise, not interested in his revelations, and discouraged him from further disclosures. Gouzenko had not known about Klaus Fuchs, but he had named a low level suspected GRU agent, Israel Halperin, a mathematician, who was later completely cleared of any suspicions of espionage. When the Royal Canadian Mounted Police searched Halperin's lodgings, they found the name of Fuchs in his address book. Fuchs immediately ceased contact with his handler, Harry Gold, and shortly afterwards took a long vacation in Mexico. Wright alleges