He became outraged by the USSR's cruel crushing of the Prague Spring reform movement in Czechoslovakia in August 1968, and began sending covert signals to Danish and British intelligence agents and agencies that he might be willing to cooperate with them.

[2] MI6 allowed him to make his own decision whether to immediately defect to the UK and live thenceforth in secrecy under their protection, or to go to Moscow with the understanding that he could be interrogated, tortured, or killed if the KGB suspected his betrayal.

[2] Gordievsky felt, given the huge benefits MI6 would reap if he remained rezident of the embassy, that he was being encouraged by MI6 to return to Moscow as ordered, and decided on that;[2] MI6 began to revive a plan to extricate him if necessary.

[6][2] After returning to Moscow on 19 May 1985, Gordievsky was drugged and interrogated, but not yet criminally charged; instead he was placed in a non-existent desk job in a nonoperational department of the KGB.

[7][2] Under increasing surveillance and pressure in Moscow and seriously suspected of being a double agent, in July 1985 he managed to send a pre-arranged covert signal to MI6 to be rescued.

[9] He tried to send a covert sympathetic message to the Politiets Efterretningstjeneste (PET, Danish Security Intelligence Service) but his three-year stint ended and he returned to Moscow before making any direct contact.

[9][2] By the time he arrived again in Copenhagen in October 1972 for a second three-year stint, both the PET and MI6 – which had been tipped off by one of Gordievsky's old university friends – felt he was a persuadable agent.

Soon a high-ranking American CIA officer, Aldrich Ames, began selling secrets to the KGB and reported Gordievsky's treachery to Soviet counterintelligence.

[13] An elaborate escape plan from the USSR had been already devised for Gordievsky by MI6 in 1978, when the KGB called him back to Moscow for a few years after his second three-year stint in Copenhagen.

[14] Although he almost certainly remained under KGB surveillance, Gordievsky managed to send a covert signal to MI6, which activated the elaborate escape plan, Pimlico, that had been in place for many years for just such an emergency.

On 19 July 1985, Gordievsky went for his usual jog, but he instead managed to evade his KGB tails and boarded a train to Leningrad and then travelled on to a rendezvous south of Vyborg, near the Finnish border.

In 1990, he was consultant editor of the journal Intelligence and National Security, and he worked on television in the UK in the 1990s, including the game show Wanted.

[21] On 26 February 2005, he was awarded an Honorary Degree of Doctor of Letters by the University of Buckingham in recognition of his outstanding service to the security and the safety of the United Kingdom.

Work in recent years included being a consultant editor for the journal National Security, co-hosting a TV show titled Wanted in the Nineties and writing content for Literary Review.

[3] In April 2008, the media reported that on 2 November 2007, Gordievsky had been taken by ambulance from his home in Surrey to a local hospital, where he spent 34 hours unconscious.

[2] The 2019 edition of the book includes an Afterword of post-publication reactions from officers of MI6, the KGB, and the CIA who had been involved in the events surrounding Gordievsky.

[32] In March 2020, Gordievsky's story was recounted in an episode of Spy Wars With Damian Lewis, on the Smithsonian Channel in the US, streaming on various cable services.

[33] In 2023, the third episode of Netflix docuseries Spy Ops named "Operation Pimlico" shows the story of Gordievsky's extraction from Moscow orchestrated by MI6, shortly after he suspects his cover may have been blown.

In May 2024 the BBC aired a four-part spy documentary series called Secrets & Spies: A Nuclear Game, which examined Gordievsky's vital work for British Intelligence, stopping Operation Able Tracer, helping NATO build peaceful relationships with Mikhail Gorbachev, and Gordievsky's dramatic escape from the Russian/Finland border.