Shamima Begum accepts she joined a terror group

"We tried so hard to clear up our tracks and just one of us was stupid," she said.

Ms Begum said they tried to pack light for the journey. "People used to say like, pack nice clothes so you can dress nicely for your husband but I don't know," she said, referring to the fact that they were expected to marry IS fighters.

While they showed sophistication in concealing their intentions to join IS, other aspects of their planning betrayed the age of the teenage runaways.

Ms Begum said she stocked up with chocolate bars that she knew she would not be able to buy in Syria: "about 30" mint Aero bars.

"You can find a lot of things in this country but you cannot find mint chocolate," she said.

One woman who went to school with Ms Begum said she had been "a ghost", who was quiet and kept to a small friendship group.

Ms Begum says her family "thought I was too, like, weak to do something so crazy, so they did not think in a million years I could do that" - referring to her recruitment by IS.

"I've always been a more secluded person. That's why it's so hard the way my life has turned out being all over the media because I'm not a person that likes a lot of attention on me," she told the