Shabana Mahmood has said she will 'robustly defend' the decision to revoke Shamima Begum's citizenship as the Home Secretary gears up to take on the European Court of Human Rights.
Yesterday, the ECHR formally asked the Home Office whether it broke human rights and anti-trafficking laws - which is Begum's main legal argument.
Lawyers for the former London schoolgirl hailed the request as an 'unprecedented opportunity'.
But the move has put Ms Mahmood on collision course with Strasbourg after a Government source indicated the Home Secretary was prepared to fight any challenge to the decision to revoke the ISIS bride's citizenship.
'The Home Secretary will robustly defend the decision to revoke Shamima Begum's citizenship, which has been tested and upheld time and again in our domestic courts. The Home Secretary will always put this country's national security first,' the source said.
Meanwhile, the Tories have backed the Home Secretary and insisted Begum should not be allowed back into the UK 'under any circumstances'.
Shadow home secretary Chris Philp said: 'Begum chose to go and support the violent Islamist extremists of Daesh, who murdered opponents, raped thousands of women and girls and threw people off buildings for being gay.
'She has no place in the UK and our own Supreme Court found that depriving her of citizenship was lawful.
The Home Secretary Shabana Mahmood will 'robustly defend the decision to revoke Shamima Begum's citizenship' putting her and the Home Office on collision course with Strasbourg
Begum, who lived in Bethnal Green, was found in a Syrian refugee camp in 2019 after her travel to ISIS-controlled territory in the country as a 15-year-old in 2015
'It is deeply concerning the European Court of Human Rights is now looking at using the ECHR to make the UK take her back.'
Begum, who lived in Bethnal Green, was found in a Syrian refugee camp in 2019 after her travel to ISIS-controlled territory in the country as a 15-year-old in 2015.
Her UK citizenship was immediately revoked by then-home secretary Sajid Javid on national security grounds, kickstarting a lengthy legal challenge by Begum.
She lost an appeal in February 2023 against the decision to revoke her citizenship after the Special Immigration Appeals Commission (SIAC) ruled this was lawful.
Begum then lost a Court of Appeal bid in February 2024, before she was most recently denied the chance to challenge it at the Supreme Court in August 2024.
However, Begum's lawyers warned at the time that they could still take her case to the European Court of Human Rights - which they later did.
In a document published by the European court in December, it states Ms Begum is challenging the decision under Article 4 of the European Convention on Human Rights - prohibition of slavery and forced labour.
The case was lodged in December 2024 after she was denied the chance to challenge the removal of her British citizenship at the UK's Supreme Court.
Among four questions posed by judges in Strasbourg to the Home Office, it asked: 'Did the Secretary of State have a positive obligation, by virtue of Article 4 of the Convention, to consider whether the applicant had been a victim of trafficking, and whether any duties or obligations to her flowed from that fact, before deciding to deprive her of her citizenship?'
Responding to the move, Birnberg Peirce Solicitors, which is representing Begum, said the court's communication 'presents an unprecedented opportunity' for the UK and Begum to 'grapple with the significant considerations raised in her case and ignored, sidestepped or violated up to now by previous UK administrations'.
Lawyer Gareth Peirce said: 'It is impossible to dispute that a 15-year-old British child was in 2014/15 lured, encouraged and deceived for the purposes of sexual exploitation to leave home and travel to Isil-controlled territory for the known purpose of being given, as a child, to an Isil fighter to propagate children for the Islamic State.
'It is equally impossible not to acknowledge the catalogue of failures to protect a child known for weeks beforehand to be at high risk when a close friend had disappeared to Syria in an identical way and via an identical route.
'It has already been long conceded that the then home secretary, Sajid Javid, who took the precipitous decision in 2019 very publicly to deprive Ms Begum of citizenship, had failed entirely to consider the issues of grooming and trafficking of a school child in London and of the state's consequent duties.'
A Home Office spokesperson previously told the Daily Mail: 'The Government will always protect the UK and its citizens.
'That is why Shamima Begum - who posed a national security threat - had her British citizenship revoked and is unable to return to the UK.
'We will robustly defend any decision made to protect our national security.'
In October, the Government announced that extremists stripped of their British citizenship would no longer be able to regain their status after a successful first appeal as a new law came into force.
Beforehand, a person who the Government considered a threat to national security could have been released from immigration detention or returned to the UK while further appeals to stop them were ongoing.
But the new law closed this loophole so that citizenship cannot be regranted until all appeal proceedings have been completed.
Between 2018 and 2023, an average of 12 people a year were deprived of their citizenship on the grounds it was 'conducive to the public good'.
This decision is made by the home secretary in serious cases where it is believed to be in public interest for reasons such as terrorism or serious organised crime.