George Osborne and William Hague have rounded on Labour for acting "opportunistically" over Syria and appeared to quash the possibility of going back to MPs to seek support for military action.
David Cameron ruled out the use of British force following a humiliating defeat in the Commons but the prospect of Parliament revisiting the issue was raised following US president Barack Obama's announcement that he is seeking congressional support for a punishment strike on Bashar Assad's regime.
Mr Osborne has insisted , however, that "Parliament has spoken" and suggested that even in the face of fresh chemical weapons attacks or new evidence, Britain will not intervene. Mr Hague said it was not "realistic" to repeatedly return to the Commons with the same question.
The Chancellor and Foreign Secretary both acknowledged that many Coalition MPs were deeply sceptical about intervention and were unlikely to change their position, even in the face of further evidence.
They hit out at Labour for its "partisan" position and claimed the party's decision had raised "serious concern" in capitals across Europe as well as in Washington.
US Secretary of State John Kerry has revealed the United States has evidence of sarin gas use in Syria and insisted he is confident that Congress will back military action when it is put to a vote next week.
Mr Hague insisted relations between the US and the UK remain strong and said Britain will provide diplomatic and political support but issued a stern warning to Labour.
Former Liberal Democrat leader Lord Ashdown suggest British support could be put back on the table after President Obama announced last night that he is seeking congressional support, telling the BBC parliament could "reconsider its position".
Labour sources insisted that the party had "never ruled out force in principle" but simply could not sign up to the motion the Government had tabled. Members of the shadow cabinet would not be drawn on whether they would support military action if the situation in Syria changed.
Shadow defence secretary Jim Murphy said if there was evidence that al Qaida elements in Syria had chemical weapons, then David Cameron had "a right" to bring the decision on military action back to Parliament.