Jack Letts, also known as 'Jihadi Jack', has reportedly been stripped of his UK citizenship.
The 24-year-old, who holds dual nationality through his Canadian father John Letts and British mother Sally Lane left his Oxfordshire home in 2014 to allegedly fight with the so-called Islamic State in Syria.
The Home Office decision was first reported by the Mail On Sunday and then confirmed by ITV News sources.
ITV News understands the decision was signed off during the final days of the Theresa May administration, but the new Home Secretary, Priti Patel, had the option to overrule her predecessor.
The Briton exclusively told ITV News in February he wanted to come home after being held for two years in a Kurdish prison - saying he missed the home comforts of British life, including pasties and episodes of Doctor Who.
Jack admitted to ITV News in the interview that he had freely joined the terrorist organisation, he said: "Obviously that’s why I said people believe me to be a terrorist...terrorist…it depends on your definition…‘one man’s…’ that’s the wrong thing to use.
"I understand...I was an idiot. Like I said, I’m not trying to make myself innocent…according to this definition of course I was a terrorist. But it is not the life I want to lead now. That’s not why I left. If I wanted to stay as an idiot …I wouldn’t have left."
A Home Office spokesperson said: "Decisions on depriving a dual national of citizenship are based on substantial advice from officials, lawyers and the intelligence agencies and all available information.
"This power is one way we can counter the terrorist threat posed by some of the most dangerous individuals and keep our country safe."
The latest decision follows a move by the then Home Secretary Sajid Javid to strip Islamic State bride Shamima Begum of her British citizenship in February, after the 19-year-old turned up in a refugee camp in Syria ahead of the fall of the group’s self-proclaimed territorial caliphate.
Ms Begum was one of three girls from Bethnal Green, east London, who left the UK aged just 15 in February 2015 and travelled to Syria to join Islamic State.
Under international law, a person can only be stripped of their citizenship by a government as long as it does not leave the individual stateless.