The father of an MP's assistant suspected of spying for Russia has said he is shocked by her detention and attempts to deport her from the UK.
Andrei Zatuliveter told the BBC his daughter Katia, 25, is innocent and his priority now is to clear her name.
Speaking at the family home in the North Caucasus, he said claims that he himself has a KGB past were "rubbish".
The aide to MP for Portsmouth South Lib Dem MP Mike Hancock has said she feels sure she will win her case.
Mr Zatuliveter told the BBC: "I always thought that England was a democratic country. People cannot be detained for no reason."
He said if his daughter could be treated like that, then anyone in Britain could be yanked by the collar and kicked out of the country without an official explanation.
British officials have indicated that to meet a deportation order, the case against the Russian researcher does not have to be "beyond reasonable doubt".
The Home Office has not confirmed whether there are plans to deport her.
Meanwhile, the Russian foreign ministry said the UK government had not yet responded to its request for more information on the case or its offer to provide consular assistance to its citizen.
In an official statement on its website, it said: "As for the eagerness with which some media in the UK are trying to stage a 'vaudeville' about the worn-out spy plot, this cannot fail to awaken pity.
"We have no illusions that in Britain there are and will be highly influential forces, who are not interested in normalisation of Russian-British relations. We hope, however, that the London government's stated policy of improving bilateral cooperation will be reinforced by concrete acts."
Miss Zatuliveter was taken into custody on Thursday, reportedly on the orders of MI5, because her presence was alleged to be not "conducive to national security".
She was first stopped in the summer and has been interviewed by police four or five times since.
'I will win'
The researcher started working for Mr Hancock in 2008 and had previously been an intern at the House of Commons and worked in Europe.
She is alleged to be the first Russian spy caught in the British Parliament since the Cold War.
Miss Zatuliveter vowed to fight her deportation case in an e-mail sent to the BBC Russian Service from the immigration centre where she is being held.
She wrote: "I was arrested on Thursday at 7am and was told I would be deported. Nobody explained me why and this is my main concern.
"I was not told about the arrangement of the flight. I am in the process of appealing against the deportation and absolutely sure I will win it (if there is justice)."
Mr Hancock, who sits on the House of Commons Defence Select Committee, has backed Miss Zatuliveter, saying she was not involved in any sensitive work.
He said he had "no reason to believe she did anything but act honourably during the time she was working for me".
Foreign Secretary William Hague has said the government was "vigilant" about the risk of foreign spies in Whitehall.
The latest allegations come after 10 Russian agents, including Anna Chapman, who had dual Russian-UK citizenship, were expelled from the US in July.