British counter-intelligence service appears to have been near-perfect". The Labor Government was defeated at the December 1949 federal election, and in March 1950 the new prime minister, Robert Menzies, appointed the Deputy Director of Military Intelligence, Charles Spry, as the second Director-General of Security, commencing on 9 July 1950. Wake resigned shortly after Spry's appointment. On 6 July 1950, a Directive of Prime Minister Menzies set out the Charter of the Australian Security Intelligence Organization, which expanded on Chifley's 1949 Directive. ASIO was converted to a statutory body on 13 December 1956 by the Australian Security Intelligence Organisation Act 1956 (later repealed by the Australian Security Intelligence Organisation Act 1979, the current legislation as amended to 2007). Spry would continue to hold the post until January 1970. The spelling of the organisation was amended by legislation in 1999 to bring it into line with the Australian standard form 'organisation'. The operation to crack the Soviet spy ring in Canberra consumed much of the resources of ASIO during the 1950s. This operation became internally known as "The Case". Among the prime suspects of the investigations were Wally Clayton, a prominent member of the Australian Communist Party, and two diplomats with the Department of External Affairs, Jim Hill and Ian Milner. However, no charges resulted from the investigations, because Australia did not have any laws against peacetime espionage at the time. The Petrov Affair 5 February 1951 saw the arrival in Sydney of Vladimir Mikhaylovich Petrov, Third Secretary of the Soviet Embassy. An ASIO field officer identified Petrov as a possible 'legal', an agent of the Soviet Ministry of State Security (MGB, a forerunner to the KGB) operating under diplomatic immunity. The Organisation began gently cultivating Petrov through another agent, Dr. Michael Bialoguski, with the eventual goal of orchestrating his defection. Ultimately, Petrov was accused by the Soviet Ambassador of several lapses in judgement that would have led to his imprisonment and probable execution upon his return to the Soviet Union. Petrov feared for his life and accepted the defection life-line provided by ASIO. The actual defection occurred on 3 April 1954. Petrov was spirited to a safe house by ASIO officers, but his disappearance and the seeming reluctance of Australian authorities to search for him made the Soviets increasingly suspicious. Fearing a defection by Petrov, MVD officers dramatically escorted his wife Evdokia to a waiting aeroplane in Sydney. There was doubt