David Cameron: Proof grows that President Assad used sarin in Syria's civil war

The deadly nerve agent sarin does appear to have been used by Bashar Assad’s regime during Syria’s two-year civil war according to a “growing body of limited but persuasive information”, David Cameron has told MPs.

The Prime Minister, who is to fly to Russia for talks with President Vladimir Putin on Thursday, warned that a proper negotiation to “force a political transition” was urgent. He told the House of Commons there was reason to believe “... the regime has used and continues to use chemical weapons, including sarin. And the room for doubt about this continues to diminish”.

Mr Cameron’s official spokesman said he would also be using his talks with Mr Putin to discuss next month’s summit of G8 leaders in Lough Erne, Northern Ireland.

Russia and the US have been deeply split on the best solution in Syria but said they would work to revive a transition plan initially laid out in 2012, and they were committed to bringing the regime and rebels to the table to end fighting which, the UN estimates, has cost 70,000 lives since March 2011.