Shamima Begum will appeal the government’s decision to strip her of British citizenship at a specialist court hearing on Tuesday.
At the time she said she wished to return to the UK, despite declaring she did not regret joining Isis.
But Sajid Javid, who was then home secretary, responded by stripping Begum of her citizenship. The former Isis bride’s family have now taken legal action in an attempt to overturn the decision.
The case will be considered during a four-day preliminary hearing before the Special Immigration Appeals Commission (SIAC) starting on Tuesday.
Elisabeth Laing, a High Court judge, is expected to consider whether depriving Ms Begum of her citizenship left her stateless.
Under UK law a person can legally have their citizenship revoked but they cannot be made stateless.
Mr Javid stripped the 20-year-old of her status on the grounds her Bangladeshi heritage meant she could claim citizenship there instead.
Tasnime Akunjee, the Begum family’s lawyer, previously told The Independent that she “never had a Bangladeshi passport”.
Bangladesh has also said the former Isis bride is not a citizen and cannot enter the country.
Individuals appealing to SIAC usually remain anonymous, but it is understood Ms Begum has waived her right to anonymity.
She was previously married to Yago Riedijk, an Isis fighter who she said was later arrested and tortured by the jihadist group.
She had two children while living under the caliphate, who both later died.
She gave birth to a third child while in the Al-Hol camp. The baby boy has since also died.
Kadiza Sultana is believed to have been killed by airstrikes in 2016. It is unclear if Amira Abase is alive.
Mr Javid’s successor, Priti Patel, has also flatly ruled out allowing Ms Begum to return to the UK.
“Our job is to keep our country safe,” she told The Sun last month.
“We don’t need people who have done harm and left our country to be part of a death cult and to perpetuate that ideology.”
The status of British citizens who travelled to Syria to join Isis has triggered extensive public debate since Begum was found.
At least 60 British children remain trapped in northern Syria, according to Save the Children.
Additional reporting by agencies
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