When Sonya arrived in England in January 1941 the surveillance of subversive movements in Britain by MI5 was carried out by B Division, which was then divided into four sections – B.1., B.4.a., B.4.b. and B.7., and had a total staff of seven. B.4.a., which was responsible for monitoring communists and Trotskyists, consisted solely of Roger Hollis as head, his assistant Miss H. Creedy and Miss W. Ogilvie. Miss Ogilvie had only joined the section, on 27 August 1939. During the war the section also began to monitor pacifists, and in April 1940 recruited a Mr Fulford to specialize in this side of the work. The section known as B.4.b. (originally B.15) dealt specifically with enemy espionage through industry and commerce. It was particularly concerned with the possibility of espionage inside firms who had access to government departments and were either supplying or servicing goods to naval, military, or air establishments and factories engaged on government work. (In certain cases industrial and commercial spying was dealt with by B.1.c., usually because specific technical questions were involved.) Although Nazi Germany was the principal enemy during the Russo-Finnish war (November 1939 to March 1940) the Soviet Union came to be regarded as a major threat. As a result of Comintern instructions that the war should be opposed as a conflict between the imperialist powers, the CPGB found itself the target of much government hostility. A top secret plan was drawn up by Britain's Chiefs of Staff (Operation Pike) to launch a series of air strikes against Soviet oilfields in the Caucasus, and a joint Franco-British expeditionary force was assembled from among men already conscripted for the war against Germany. At the same time a number of high-level espionage cases, linked with members of the USSR trade delegation from their offices in Hatton Garden, came to the fore. One such case, which had come to light in December 1939, was that of Alexsey Alexandrovich Doschenko, Director of engineering of the USSR trade delegation, who had attempted to gain secret information on gun turrets and the position, housing and release of bombs from a worker at an important aircraft factory. The following month Doschenko was deported. At the time of his deportation surveillance activities against members of the Soviet trade delegation were stepped up, causing considerable anxiety for the Soviet Embassy in London.