The Government has revoked the British passport of Russian spy Anna Chapman, sources have said.
Chapman, 28, who was married to a British man and lived in London for several years, was expelled from the US in the biggest spy swap since the Cold War.
She was flown back to Moscow last week, but her American lawyer said she would like to return to Britain.
But a Whitehall source said Chapman has been handed a letter revoking her citizenship and her passport is no longer valid.
Officials revealed Home Secretary Theresa May was urgently considering the case last week. She has the power to deprive dual nationals of citizenship when to do so would be "conducive to the public good".
Chapman was one of 10 Russian spies exchanged for four Western agents released by Moscow in a spy swap on the tarmac at Vienna airport with echoes of the Soviet era.
They were expelled from the US after pleading guilty in a Manhattan court to conspiracy to act as an unregistered agent of a foreign country.
Details emerged after their arrests last week of how they led apparently ordinary lives in America - several were married with children and had well-kept suburban homes - while acting as undercover agents. Members of the spy ring were said to have sent information from the US back to Moscow in a plot reminiscent of a James Bond novel, using invisible ink, false passports and code words.
Chapman, the daughter of a Russian diplomat, was married to Briton Alex Chapman, 30, from Bournemouth, Dorset, from 2002 until 2006 and worked in London for about four years.
Mr Chapman has spoken of his suspicions that his ex-wife was being "conditioned" by shadowy Russian contacts during their marriage.
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