A British man has been arrested in Germany on suspicion of spying for Russia.
German federal prosecutors said the man – named only as David S – worked at the British embassy in Berlin.
He allegedly passed documents to Russian intelligence “at least once” in exchange for an “unknown amount” of money.
He was arrested in Potsdam outside Berlin on Tuesday and his home and workplace have been searched.
A spokesman for Germany’s foreign ministry quoted by AFP news agency said Berlin was taking the case “very seriously”, and said spying by “a close alliance partner on German soil is unacceptable”.
The arrest was the result of a joint UK-German investigation, the statement read.
It was intelligence-led and had been going on for some time leading up to the arrest, the BBC’s Security Correspondent Gordon Corera says. MI5 and other UK agencies, as well as British police, had been working with the Germans to learn as much as they could about the alleged activity.
London’s Metropolitan Police confirmed the arrest of a 57-year-old British national in Germany, as well as the involvement of the Met’s Counter Terrorism Command.
German authorities are in charge of the investigation, but officers will continue to work with German counterparts, the police said.
The man is due to appear before an investigating judge on Wednesday.
Prosecutors said he was hired as a local staff member at the embassy.
German online news site Focus Online reports that the documents passed on were to do with counter-terrorism and that the man is not thought to have diplomatic immunity.