A Russian woman working for a British lawmaker is facing deportation after security services detained her on suspicion of espionage, the Sunday Times reported on Sunday.
The paper claimed that Katia Zatuliveter, 25, secretly worked for the Russian intelligence as a "sleeper" agent.
She had been for working for Liberal Democrat MP Mike Hancock who denied his assistant had done anything wrong.
"She is not a Russian spy. I know nothing about espionage, but she has been subjected to a deportation order," Hancock said in a statement.
He said she would appeal moves to deport her.
A spokesman for the Liberal Democrat party, the junior partner in Britain's coalition government, said it was his understanding she was in custody.
A security source told the Sunday Times Zatuliveter's presence was not "conducive to national security", and the intention was to "show her the door".
The paper said it was the first time since the end of the Cold War that someone working in parliament had been accused of spying for the Russians.
Russian woman accused of being spy in British parliament
A Russian woman working for a British lawmaker is facing deportation after security services detained her on suspicion of espionage.