There are certain images that engender horror in every parent: for instance, the photograph of two-year-old James Bulger being led away from the New Strand Shopping Centre in Bootle in 1993, or Kevin Carter’s photograph from the same year of a starving child being watched over by a vulture during the famine in Sudan.

For me, though, one of the worst is the grainy CCTV image showing three teenage girls, Kadiza, Amira and Shamima, at Gatwick airport in 2015, preparing to board a Turkish Airlines flight to Istanbul. They were making their way to join ISIS. All three were ‘good girls’, who had studied hard for their exams at Bethnal Green Academy. Shamima, the quietest of the three, was a fan of the Kardashians. Why would they imagine that their lives would be better in Syria? What was it about the prospect of leaving east London for an ‘exotic’ adventure in which they would serve Allah that appealed?

These are just two of the questions that Azadeh Moaveni addresses in this extraordinary book. Moaveni is a distinguished American-Iranian journalist. Her books include Lipstick Jihad (on Iranian youth culture) and a memoir entitled Honeymoon in Tehran. She is also co-author, with Nobel laureate Shirin Ebadi, of Iran