The Prime Minister has said he is “appalled” after another attempted arson attack at a north-west London synagogue following a spate of similar incidents.Counter-terror police are leading probes into multiple arson and attempted arson attacks at Jewish sites in the area in the past month.Officers on “deterrence and reassurance patrols” in the wake of the previous incidents spotted damage to a window of Kenton United Synagogue, Harrow, at around midnight on Sunday. A “bottle with some sort of accelerant had been thrown through the window” and smoke was seen inside a room, a Metropolitan Police spokesperson said.“The incident is being...