ABSTRACT
MASK necessarily ceased as a source when Olga Gray was revealed as an MI5 agent, even though her true name was never disclosed at the Old Bailey trial of Percy Glading and his co-conspirators. Born Samuel Ginsberg, Walter Krivitsky for years had been a key figure in the GRU's illegal military intelligence apparatus in Western Europe. While Krivitsky claimed to know little about the Communist Party of Great Britain, he knew immeasurably more than the Security Service about the relationship between the Party, its underground membership and Moscow's spy-rings. According to Krivitsky, Deutsch had been subordinate to the legal rezident at the Soviet Embassy, Anton Schuster, and then Theodore Mally, alias Paul Hardt, his illegal counterpart in London between 1936 and June 1937. In the spring of 1936, through Krivitsky's intervention, Goold-Verschoyle had realised his ambition of visiting Russia and had been a student at Abramoff's radio school in Moscow.
