UK Foreign Secretary William Hague has said his counctry has decided to recognise the Syrian opposition coalition.
He told MPs the National Coalition of the Syrian Revolutionary and Opposition Forces was the “sole legitimate representative” of the Syrian people.
He said they were now a “credible” alternative to the Assad government.
In the absence of a diplomatic solution, he told MPs the UK would not rule out any action – subject to international law – to save lives.
Up to 30 000 people have been killed in the 18-month conflict, the UK believes.
Those trying to bring down President Bashar al-Assad’s government moved closer to a united front when the rival leaders of Syria’s rebels formed the coalition after months of bitter division.
At a meeting last week, Britain urged the newly formed coalition of opposition groups to put forward a clear plan for political transition in Syria.
In a statement to Parliament, Hague said the Syrian opposition would be invited to appoint a political representative to the UK and would be given £1.6 million to help with communications equipment.
The UK will also offer assistance to help the coalition set up political and humanitarian structures and deploy a “stabilisation response” team in Syria to help provide basic services to people in opposition-controlled areas.
Hague said the decision to recognise the opposition was taken after consultation with European partners and after its leaders offered “assurances” about their commitment to uphold human rights and work for a democratic future at a recent meeting.
“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 added.
“A credible alternative to the Assad regime is emerging that has the growing support of the Arab League, the European Union, the United States and an increasing number of other countries.”