Video: Woman accused of being Russian spy allowed to stay in Britain
Katia Zatuliveter, a former parliamentary aide who was accused of being a Russian spy has won her battle to remain in the UK after arguing that she was not passing secrets to Moscow.
Zatuliveter, 26, convinced the Special Immigration Appeals Commission (Siac) that she was not liaising with Russian spies while working for MP Mike Hancock, a member of the Defence Select Committee, with whom she had an affair.
Despite not being allowed to attend large parts of the Siac hearing - much of it held behind closed doors with evidence from security services spies - Zatuliveter convinced the panel she was not a danger to national security.
The Home Office said it was disappointed with the ruling.
A spokeswoman said: "National security is the primary duty of government and we will take all necessary steps to protect the public from individuals we believe pose a threat and remove them from the UK.
"The court ruled that there were ample grounds for suspicion.
"We are therefore very disappointed by the court's judgment and stand by our decision to pursue deportation on national security grounds."
Miss Zatuliveter smiled as Mr Justice Mitting announced that she had won her appeal to remain.
Her solicitor, Tess Gregory, said: "Katia is, of course, delighted by the judgment and hopes to now put this episode behind her.
"However, it should not have taken 12 months of costly legal proceedings to reach today's outcome.
"If the Security Service, like the court, had rigorously analysed the available evidence, they would never have concluded that she was a Russian spy and we would not be here today.
"Our Security Service is supposed to be responsible for protecting us against serious threats to national security.
"It is therefore extremely worrying that they have chosen to waste their time, at great public expense, needlessly and unfairly pursuing an innocent young woman.
"Their case was built entirely on speculation, prejudice and conjecture.
"It was amateur, poorly researched and compared very unfavourably to the counter-espionage work conducted by the FBI in recent years."