What will become - what should become - of Jack Letts? HARDtalk's Stephen Sackur speaks to his parents, Sally Lane and John Letts. Alongside the humanitarian fall-out from Turkey’s invasion of northern Syria, there are grave security concerns - not least what will happen to the thousands of so-called Islamic State militants imprisoned by Syrian Kurdish forces. British-born Jack Letts left the UK in 2014 to live in the so-called IS Caliphate. Since then, he’s had his British citizenship revoked, and his parents have been convicted under UK anti-terror laws for sending him money.