On the day the caliphate suffered a mortal blow the teenage London bride of an Islamic State fighter lifted her veil. Her two infant children were dead; her husband in captivity. Nineteen years old, nine months pregnant, weak and exhausted from her escape across the desert, she nevertheless looked calm and spoke with a collected voice.

“I’m not the same silly little 15-year-old schoolgirl who ran away from Bethnal Green four years ago,” she told me. “And I don’t regret coming here.”

With those words and the act of lifting her niqab, a mystery ended. The girl sitting before me, alone in a teeming Syrian refugee camp of 39,000 people where she is registered as No 28850, was Shamima Begum, the only known survivor