Fewer than half of British voters now support airstrikes against Islamic State in Syria after five million people turned against military action in the past week, a poll for The Times has found.

With MPs expected to give approval for strikes tonight, the YouGov survey found that support for the move had plunged from 59 per cent to 48 per cent since David Cameron set out his case last week. YouGov said that the decline equated to five million voters turning against a bombing campaign.

The proportion opposed to airstrikes has increased by 11 points, from 20 per cent to 31 per cent, with 21 per cent undecided. The gender gap has widened sharply: men now favour action by more than two to one (58