Muslim children as young as five have become so indoctrinated by Islamist propaganda they believe Christmas is sinful, Britain’s most senior Muslim police officer warned yesterday. Scotland Yard commander Mak Chishty said children had voiced opposition to marking the festive holiday—branding it “haram”, which means forbidden by their god Allah. He said that parents need to address “all the ugly bit of the problem”, and ask how children had come to that view. Mr. Chishty also warned of a need for parents to spot early signs of radicalization, which could include their sons and daughters refusing to shop in certain...