The order to arrest radical cleric Abu Qatada may have been issued too soon, and before a critical deadline to ask for an appeal at the European court had passed, it has emerged.
The Home Office had ordered Qatada's arrest on Tuesday on the grounds that a three-month period in which he could ask for an appeal at the Grand Chamber of the European Court of Human Rights had expired.
The UK Border Agency (UKBA) arrested Qatada hours after the deadline.
But at the start of what could be another lengthy legal battle, Qatada's legal team argued that they still had time to lodge the appeal and did so just before midnight on 17 April.
They claim that judges at the court were wrong three months ago when they ruled that he would not be at risk of torture if returned to Jordan.
Confusion remains over whether the appeal will now be heard. The European Court of Human Rights said the case for the appeal can be heard, and that the timing will be "considered", according to the BBC.
The Home Office has denied that Qatada filed the appeal in time.
In a statement they said: “Qatada has no right to refer the case to the Grand Chamber of the European Court of Human Rights, since the three-month deadline to do so lapsed at midnight on Monday night.
"His case should be heard in British courts, as the home secretary outlined to Parliament yesterday. In the meantime, he remains in custody.”
Prime Minister David Cameron said he was determined that Qatada would be deported, no matter how long it took.
"I am absolutely clear, the entire government is clear, and frankly I think the country is clear, that this man has no right to be in our country.
"He is a threat to our security, he has absolutely no further call on our hospitality and he should be deported.
"That is what we are determined to achieve, no matter how difficult it is, no matter how long it may take," he said.
Speaking to the BBC, May described Qatada's application to the European court as a "delaying tactic" prompted by his awareness of the strength of the case for his deportation set out by the government.
She rejected suggestions that the Home Office may have blundered in its calculation of when the deadline for an appeal would come, and said there "no question" of the government having broken the law by arresting Qatada too early.
The treaty governing the European court states that referrals must be made within three months of a judgment, and court officials were "absolutely clear" that the UK was working on the basis that in Qatada's case this expired at midnight on April 16, said the home secretary.
However, the application was not automatically struck out if it was received after the deadline and it was now for the Grand Chamber to decide whether the court should hear it.
"The decision as to whether or not Abu Qatada remains in prison will be one that will be taken by the UK courts, if he chooses to apply for bail. Obviously, if he does, we will oppose that bail vigorously, as we did yesterday - we argued for his detention yesterday - and as we have done in the past," she said.
The move by Qatada's legal team is separate from any appeal they may make over Tuesday's decision by Home Secretary Theresa May to continue with his deportation.
Instead it relates to a different strand of the original decision of the Strasbourg-based court which found that the 51-year-old would not face being tortured himself if deported.
Under the rules of the court, all parties have three months in which to appeal to the court's Grand Chamber before the decision becomes final.
According to the European court, a panel of judges will now have to decide whether the case can be hear at the court's Grand Chamber.
Qatada, who has been described by a judge as Osama bin Laden's right hand man in Europe, was arrested at his London home by UK Border Agency (UKBA) officers on Tuesday.
His arrest marked the start of the government's latest bid to deport Qatada, who was returned to jail after a rapidly convened court hearing found deportation was imminent and the chance of Qatada trying to abscond had increased.
But May yesterday warned MPs that it may still be "many months" before Qatada can be lawfully kicked out, even though they were confident of its "eventual success".
Qatada was released from Long Lartin high-security jail in Evesham, Worcestershire, in February under some of the toughest bail conditions seen since the September 11 attacks.
It came after Europe's human rights judges in Strasbourg ruled that he could not be deported to Jordan without assurances that evidence gained through torture would not be used against him.
May said: "I believe the assurances and the information we have gathered will mean that we can soon put Qatada on a plane and get him out of our country for good."
She added: "Deportation may still take time. The proper process must be followed and the rule of law must take precedence.
"But today Qatada has been arrested and the deportation is under way."
Edward Fitzgerald QC, representing Qatada, said the arguments for deportation were based on "a series of unsubstantiated claims".
Qatada, who is said to have "wide and high-level support" among extremists, was convicted in his absence in Jordan of involvement with terror attacks in 1998 and now faces a retrial in his home country.
He also featured in hate sermons found on videos in the flat of one of the September 11 bombers.
Since 2001, when fears of the domestic terror threat rose in the aftermath of the attacks, he has challenged, and ultimately thwarted, every attempt by the government to detain and deport him.
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