The femme fatale at the heart of the US-Russia spy scandal was stripped of her British passport yesterday. The Home Office announced that the citizenship of Anna Chapman had been revoked, and she is also likely to be banned from travelling to the country at all.

Ms Chapman, the 28-year-old redhead who gained her UK passport through her 2002 marriage to a British trainee psychologist, has been the most high-profile of the 10 Russian deep-cover agents arrested in the US last month and deported to Moscow as part of a high-profile swap last week.

Ms Chapman and the other nine landed in Moscow last Friday after an exchange on the tarmac at Vienna. A source in the Russian security services told Moskovsky Komsomolets newspaper yesterday that the 10 were taken straight from the plane to the headquarters of the Russian intelligence service, the SVR, at Yasenovo in the south of Moscow.

Their exact current location was unknown but the source said they were being held in one of the SVR's secret 'guesthouses', which are sealed to the outside world, with no internet access or mobile phone reception. The spies may receive visits from family but are not allowed to leave the compound.

"At the current time, specialists are working with the agents," the source told the Russian newspaper. "They are trying to find out which of the agents blew their cover and in what situation. To get to all the details there are interrogations and various tests, including lie detector tests... If it turns out that serious mistakes were made, then the spies could be fired."

In a bizarre coincidence, it emerged yesterday that one of the spies had raised the suspicions of the granddaughter of Soviet leader Nikita Khrushchev. Nina Krushchev had served as the faculty adviser of the man who went by the alias of Richard Murphy at The New School in New York City where she teaches media and culture.

"He had a thick Russian accent and an incredibly unhappy Russian personality," she said. "I knew he wasn't American. I knew it was very odd. I never bothered to ask him, though, because I was afraid to become privy to some random Russian drama."

US officials revealed yesterday that another Russian citizen has been detained in connection with the spy ring. The 23-year-old man, who was not named, entered the United States last October, said officials, and had been tracked ever since. There was not enough evidence to charge him with a crime, but he was expected to be deported to Russia last night.

Also yesterday, the brother of Igor Sutyagin, one of the four prisoners freed by Russia in the swap deal, revealed that his brother is staying in a hotel near London.

Dmitry Sutyagin told news agencies that Igor was in good mental condition and has met British officials who said he should receive his British visa by today.

According to his brother, the scientist, who was convicted of passing on secret information to the CIA, is undecided about whether to stay in Britain and where he wants to work.