Shamima Begum will exploit “any error” to regain her citizenship, the Court of Appeal heard.
Sir James Eadie KC, for the Home Office, said Begum knows that if the Home Office is forced to make a new decision over her future she will not have her citizenship removed again because it would render her stateless.
When the Home Office stripped her of citizenship in 2019 it said she had Bangladeshi citizenship but that no longer applies because she is over 21.
The Court of Appeal heard claims that then home secretary, Sajid Javid, should have investigated whether the state failed to protect Begum who was 15 when she went to join ISIS in 2015.
Sir James, representing the Home Office, told the court: “The position as we understand it now is that Begum, now past the age of 21, is no longer a dual citizen.
“So when it comes to the original decision, for the opposition, any error will do because they know in any future decision statelessness will rear its head, which will perhaps be a gamechanger.”
Begum, now 24, will face a wait to find out whether she has won a Court of Appeal bid over the removal of her British citizenship.
She travelled to Syria in 2015 to join the Islamic extremist death cult, at the age of 15, before her citizenship was revoked on national security grounds in 2019.
Earlier this year, Begum lost a challenge against the decision at the Special Immigration Appeals Commission (SIAC).
Begum’s lawyers brought a bid to overturn this decision at the Court of Appeal, with the Home Office opposing the challenge.
At the start of the hearing on Tuesday, Samantha Knights KC told the court the government had failed to consider the legal duties owed to Begum as a potential victim of trafficking or as a result of “state failures” in her case.
She said in written submissions: “The appellant’s trafficking was a mandatory, relevant consideration in determining whether it was conducive to the public good and proportionate to deprive her of citizenship, but it was not considered by the Home Office.
“As a consequence, the deprivation decision was unlawful.”
But at the hearing in London on Wednesday, Sir James Eadie KC, for the department, said that decisions over whether someone is a victim of trafficking or whether they should be deprived of their citizenship “have fundamentally different bases and roles”.
He continued: “The focus in the trafficking regime is on the protection of the individual and there’s really no countervailing public interest at that point.
“But here the regime is different, the regime in operation is the deprivation regime and the rationale is entirely different, it is the protection of the public at large.”
The hearing in London is expected to conclude on Thursday, with the final day of the proceedings held in private.
At the end of Wednesday’s session, the Lady Chief Justice Lady Carr said: “We anticipate we will be reserving both open and closed decisions.”
