But this was no ordinary Russian defector. Mr Karakulov was an officer in President Vladimir Putin’s secretive elite personal security service –   one of the few Russians to flee and go public who have rank, as well as knowledge of intimate details of Putin’s life and potentially classified information.

Mr Karakulov, who was responsible for secure communications, said moral opposition to Russia’s invasion of Ukraine and his fear of dying there drove him to speak out, despite the risks to himself and his family.

“Our president has become a war criminal,” he said. “It’s time to end this war and stop being silent.”

Mr Karakulov’s account generally conforms with others that paint the Russian president as a once-charismatic but increasingly isolated leader, who doesn’t use a mobile phone or the internet and insists on access to Russian state TV wherever he goes.

He also offered new details about how Putin’s paranoia appears to have deepened since his decision to invade Ukraine in February 2022.

 Putin now prefers to avoid airplanes and travels  on a special armoured train, he said. H e ordered a bunker at the Russian Embassy in Kazakhstan outfitted with a secure communications line in October – the first time Mr Karakulov had ever fielded such a request.

A defection like that of Mr Karakulov “has a very great level of interest”, said an official with a security background from a Nato country.

“That would be seen as a very serious blow to the president himself because he is extremely keen on his security, and his security is compromised,” he said.

The Kremlin did not respond to requests for comment. Neither did Mr Karakulov’s father or brother.

As an engineer in a field unit of the presidential communications department of the Federal Protective Service, or FSO, Mr Karakulov was responsible for setting up secure communications for the Russian president and prime minister wherever they went.

While he was not a confidant of Putin’s, Mr Karakulov spent years in his service, observing him from unusually close quarters from 2009 through late 2022.

Mr Karakulov, his wife and his child have gone underground, and it was impossible to speak with them directly due to security constraints.

The Dossier Centre, a London-based investigative group funded by Russian opposition figure Mikhail Khodorkovsky, interviewed Mr Karakulov multiple times and shared video and transcripts of more than six hours of those interviews with members of the world’s media.

Russia’s Interior Ministry’s initiated a criminal investigation against Mr Karakulov on October 26 for desertion.

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