On Easter Sunday 1983, Bettaney, a middle-ranking MI5 officer attached to the Soviet counterespionage 
branch, wrote a letter to the KGB rezident in London, Arkadi Gouk, and delivered it to his home, confident that the Watcher Service did not have it under surveillance after midnight. In his note Bettaney supplied sufficient information about the recent expulsion of three KGB officers to impress Gouk that he had access to classified information and suggested an elaborate plan of signals and dead drops for further communication.
An Oxford graduate who had joined MI5 in 1975, Bettaney had served in Northern Ireland but had received a final warning regarding his personal behavior after a conviction for being drunk and another for fare-dodging on the train on which he commuted to London from his home in Croydon. After a further criminal conviction, which he failed to declare, Bettaney knew his career would last only until his next routine positive vetting, which would be bound to reveal his further offense and lead to his dismissal. Accordingly, he opted to sell information to the Soviets, unaware that Gouk’s deputy at the London rezidentura was Oleg Gordievsky, in whom the rezident confided. Naturally Gordievsky concurred with Gouk’s judgment that the offer was a rather crude MI5 provocation and should be ignored.
Thus, when Bettaney made a second approach, offering still further material, he was ignored. Frustrated at Gouk’s attitude, Bettaney decided to make a separate approach to the KGB in Vienna and was planning to fly there when he was arrested in September 1983 and charged with breaches of the Official Secrets Act. At his trial in April 1984 Bettaney claimed to have become disenchanted with Prime Minister Margaret Thatcher’s Conservative administration. He was convicted and sentenced to 23 years’ imprisonment. While in prison, Bettaney converted to Roman Catholicism and considered taking holy orders. He was also suspected of having leaked information about MI5’s activities in Northern Ireland to a Republican fellow prisoner. Upon his release, Bettaney moved to Hertfordshire to live with a woman who had been a prison visitor.