Dozens of jihadists could try to return to the UK after a court ruling, it is feared.
A High Court judge found a grandmother in the same camp as Shamima Begum was unlawfully stripped of her British citizenship.
The suspected Islamic State member from the north of England, known only as D4, had her citizenship removed in 2019 for what are believed to be reasons of national security.
But the judge found the woman had not been given notice, making the order invalid.
The judgment is said to have sent panic through Whitehall amid fears it could lead to up to 28 suspected jihadists claiming the right to return to the UK.
The Home Office may appeal, but Home Secretary Priti Patel could have to try to rush through a change in the law if it fails.
The woman is said to be staying at the Roj camp in northeast Syria, home to jihadi bride Begum, 21, whose bid to return to Britain sparked a national debate.
The ruling on Friday concluded: “The Home Secretary’s failure to give notice of her decision to deprive D4 of her citizenship invalidates the order.”
A Home Office spokesman said: “We are carefully considering the implications including an application to appeal.”
