Britain is to step up support for opponents of president Bashar Assad after officially recognising a newly-formed coalition of rebel groups as the "sole legitimate representative" of the Syrian people.
Foreign Secretary William Hague hailed the formation of the National Coalition of the Syrian Revolutionary and Opposition Forces as a "major breakthrough" in terms of securing a political transition from the discredited Assad regime.
The coalition would be given British assistance in establishing political and humanitarian structures, improving communications inside Syria and meeting the basic needs of people in opposition-held areas. It would also be invited to send a political representative to the UK, Mr Hague told MPs.
International Development Secretary Justine Greening is also looking at increasing British assistance to Syrians affected by the conflict, he said.
Mr Hague met the coalition's leaders in London on Friday, when they promised to keep the door open to other opposition groups, stand up for all Syrians and be a "moderate political force committed to democracy" that would not repeat president Assad's abuses.
In a statement to the Commons, Mr Hague said the group's assurances had been "encouraging" but he would be pressing them to fulfil their commitments.
The opposition alliance was formed from Syria's disparate opposition groups at a meeting in Doha earlier this month.
"It is strongly in the interests of Syria, of the wider region and of the United Kingdom that we support them and deny space to extremist groups," he said.
"On the basis of the assurances I received and my consultations with European partners yesterday, Her Majesty's Government has decided to recognise the National Coalition of the Syrian Revolutionary and Opposition Forces as the sole legitimate representative of the Syrian people."
Mr Hague refused to rule out of the prospect of Britain arming the rebels directly, although at present he said there had been no decision to change policy.