The case of Daesh bride Shamima Begum, who is appealing to retain her British citizenship and return to the UK, will go to the Supreme Court.
On Friday at a remote hearing the Court of Appeal decided that the case raised a point of public importance that only the Supreme Court can resolve.
Separately the court also heard that an investigation is under way in Whitehall as to how the Sun newspaper got hold of a copy of the previous judgement on July 16.
At the outset of Friday's hearing, Lady Justice King said: "There was a breach of the embargo which preserved the confidentiality of the judgment until hand down, the judgment having been circulated to the parties on July 9.
"Either a copy of that judgment, or the essential contents of that judgment, were disclosed or passed on to The Sun national newspaper in advance of the judgment being handed down on July 16."
Earlier this month, three Court of Appeal judges ruled that “the only way in which she [Begum] can have a fair and effective appeal is to be permitted to come into the United Kingdom to pursue her appeal.”
Lord Justice Flaux - sitting with Lady Justice King and Lord Justice Singh - said: "Fairness and justice must, on the facts of this case, outweigh the national security concerns, so that the leave to enter appeals should be allowed."
Sir James Eadie QC, for the Home Office, said there was a ‘big issue at stake’ surrounding principles that should govern a case in which someone can’t have a fair hearing, ‘not as a result of any of the Secretary of State’s actions, (but) where that is the result of going abroad and aligning with terrorist groups’. He said this ‘cannot be assumed to be unique’ given the number of people who have joined terrorist groups.
Begum, now 20, was one of three east London schoolgirls who travelled to Syria in February 2015, to join the so-called Daesh where she lived under its rule for more than three years.
She had her citizenship stripped by the UK Home Office under then-Home Secretary Sajid Javid over national security concerns after being found housed at a refugee camp in 2019, according to UK media.
Last year Begum took legal action against the Home Office and the decision of the Special Immigration Appeals Commission (Siac), which hears challenges to decisions to remove a person’s British citizenship on national security grounds.
Ms Begum told UK media that she was "just a housewife" after joining Islamic State, where she married Yago Riedijk, a Dutch rebel, and later left Raqqa in January 2017 after losing two children and a third child in 2019.
She also told the Times that she had "no regrets" about joining Islamic State and that severed heads from hostages "didn't faze" her at all.
But speaking to Sky News, she said that she had been aware of beheadings and jihadi executions but was "okay with it", stating she heard that "Islamically that is allowed".
*Daesh (aka Islamic state/ISIS/ISIL/IS) is a terrorist group banned in Russia and many other countries