Smith was transferred to the German federal court in Karlsruhe, near the French border, where he appeared before a judge and was remanded in custody after being charged with “activity as an agent for a foreign secret service” under German law. Searches were carried out at his home and the British Embassy.
Details of the information he is alleged to have passed to Russian intelligence have not been made public but, according to a report in Germany’s Focus magazine, they relate to counter-terror operations.
A security source said Smith’s alleged motivation was likely to have been money, adding that he did not have access to highly classified material. Security experts, however, said he would have been likely to have had access to security patrol schedules, how to arm and disarm alarm systems and lists of embassy staff.
On Wednesday night, Smith’s neighbours in Potsdam told Germany’s Bild newspaper that he left for work by car early each morning, returned late, and they saw little of him. They said he used to live with a woman for some years, but she had not been seen recently.
German officials suggested Smith would be likely to face trial in Germany rather than being extradited to the UK. However, British detectives are understood to have flown to Berlin to assist the investigation.
A statement from the German prosecutor said: “Until his arrest, David S worked as a local employee at the British Embassy in Berlin. On at least one occasion he forwarded documents obtained in the course of his professional activities to a representative of a Russian intelligence service.
“In return for providing information, the accused received cash in a previously unknown amount.”
The British Embassy in Berlin, opened by the Queen in 2000, is notable for the large number of private contractors who work in it.
CBRE, a company which provides facilities management, said Smith was not a member of its staff, while Securitas, which provides general security at the embassy, did not respond to requests for comment.