Does British action in Syria make military sense?
Prime Minister David Cameron has said launching UK air strikes against Islamic State militants in Syria will "make us safer".
He denied claims it would make the UK a bigger target for terror attacks, as he made the case for military action to MPs in the Commons.
Labour is split, with some shadow ministers backing bombing but leader Jeremy Corbyn opposing action.
The BBC's John Simpson reports on the arguments for and against Mr Cameron's stance.