The British man David Smith, who admitted passing secrets to Russia while working as a security guard at the British embassy in Germany, has been jailed for 13 years and two months.
The 58-year-old admitted eight charges under the Official Secrets Act.
In a televised sentencing at the Old Bailey, Mr Justice Wall said Smith had developed “decidedly anti-British” feelings and gave the impression to colleagues he was “more sympathetic to Russia, in particular President Putin”.
He said Smith’s “subversive activities” dated back to 2018 and he had copied a “significant amount of material” over the years.
The judge told Smith he was “fully aware that you should not have copied any of these documents and equally aware [that] were these documents to get into the wrong hands, they might harm British interests or pose a threat to those working at the British embassy”.
Smith began handing over documents in 2020 in a letter to a military attache at the Russian embassy and promised “more information would be forthcoming”.
In a second letter, he passed photographs of embassy staff with annotated descriptions, putting them at “maximum risk”, the judge said.
Smith’s conduct from 2020 was not a “one-off offence” and he was “paid by Russia for your treachery”, the judge said.
“You established regular contact with someone at the Russian embassy and this contact was a conduit through which material illegally obtained by you was passed on.”
Wall said Smith gathered material with a view to harming British interests in breach of the trust in his role as a security guard.
He said: “It is self-evident this case demands an immediate prison sentence.”
“I assess your culpability as high. It was your job to ensure the embassy was secure and its staff was safe.”
The judge said it was impossible to assess the actual harm Smith had caused without knowing how much information was passed on to Russia.
He added: “In taking out of the embassy personal details of staff you put all of those staff at risk of harm.”