Shamima Begum has lost her challenge over the decision to deprive her of British citizenship despite a credible case she was trafficked.
Mr Justice Jay told the semi-secret court dealing with her case that her appeal had been fully dismissed.
The decision means the 23-year-old remains barred from returning to the UK and stuck in a camp in northern Syria.
Ms Begum was 15 years old when she travelled to join the self-styled Islamic State group in 2015.
She went on to have three children, all of whom have died, after marrying a fighter with the group.
In 2019, the then home secretary Sajid Javid stripped her of her British citizenship, preventing her coming home, and leaving her detained as an IS supporter in a camp.
The Special Immigration Appeals Commission has ruled that decision, taken after ministers received national security advice about Ms Begum’s threat to the UK, had been lawful – even though her lawyers had presented strong arguments she was a victim.
