Wynne was an electrical engineer, trained at the University of Nottingham, and a businessman. He was recruited to MI5 just before World War II. He was transferred to MI6 and assisted with the 1959 defection of the Soviet intelligence officer, Major Kuznov.
He was an intermediary for the important Soviet spy Oleg Penkovsky, who was engaged in selling arms and weapons secrets to British intelligence. Penkovsky's activities were revealed by Jack Dunlap, a double-agent working for the KGB. The KGB swiftly drew the conclusion that there was a mole in their ranks and set about uncovering him.
The Soviets concluded that one of the likely conduits of information would be a British diplomat in Moscow. George Blake, a Soviet mole inside MI6, had already pointed out Ruari and Janet Chisholm as MI6 operators in the British embassy in Moscow.
Penkovsky's visits to an adjacent building identified him as a likely source of the leaks. He was arrested, giving up Wynne's name. The Chisholms were expelled from Moscow for behaviour incompatible with their diplomatic status. Wynne was arrested in Budapest and to the Soviet Union. He was convicted of spying on 11 May 1963 and sentenced to eight years in prison; Penkovsky was sentenced to death and executed (although Wynne himself in his book "The man from Odessa' claimed that Penkovsky committed suicide in prison). Wynne was released in exchange for the spy Gordon Lonsdale in 1964.
Wynne wrote about his time as a spy in a book entitled The Man from Odessa, first published in 1981. He preceded this book with The Man from Moscow: The Story Of Wynne and Penkovsky (1967) and published in the USA as Contact on Gorky Street: a British Agent's Own First-Hand Account of His Mission to Moscow (1968). This was one of the early examples of a book being published about secret work that the government never expected to be made public.
Wynne died of throat cancer at Cromwell Hospital in London on 28 February 1990, aged 70.