Britain has found a loophole to deny an Islamic bride access back to the UK.
19-year-old Shamima Begum wants to return home after giving birth at a Syrian refugee camp.
But Home Secretary Sajid Javid has blocked her request by revoking her British citizenship.
BBC diplomacy specialist Stuart Hughes told Kerre McIvor she appears to have inherited Bangladeshi citizenship through her parents.
"A person can be deprived of their citizenship if Javid was satisfied it could be conducive to the public good, but they can't leave someone stateless."
Hughes says that the UK government seems to believe that they are on a legal right foot.
He says that Begum did seem relatively unrepentant about what she had done.
"She said she was heavily pregnant and wanted to return to Britain."
Hughes says that the debate in the UK has focused on whether she is innocent or a threat to national safety.
"Some people are saying she was 15 and had no idea what she was doing. Others are saying that most 15-year-olds would know that ISIS is bad."
Begum's family said through their lawyer that they are disappointed by the decision, and are planning to appeal the decision.
Due to the crisis in Syria, Begum's family have to inform their daughter of the decision themselves as there is no UK consulate in the country.