William Hague has slapped down Nick Clegg's suggestion that "things would have been different" had the deputy prime minister been at Friday's european summit.
"I think it unlikely if he or anybody else had been there it would have been different", the foreign secretary told BBC Radio 5 Live on Sunday evening.
But speaking this morning, Nick Clegg claimed the outcome would have been different had he been present at Thursday night's summit:
"I'm not under the same constraints from my parliamentary party that clearly David Cameron is", he told the BBC's Andrew Marr programme.
Cracks have appeared in the coalition following David Cameron blocking Britain's involvement in an EU treaty.
"I'm bitterly disappointed by the outcome of last week's summit, precisely because I think now there is a danger that the UK will be isolated and marginalised within the European Union," the Liberal Democrat leader told the BBC.
"I think the prime minister was in a difficult position because he faced with intransigence from France and Germany. I have been warning for weeks privately, and publicly, that the danger at the summit was one of division, that it was clear that the French Government, for instance, would not have shed a tear if Britain was pushed", he said.
The prime minister has insisted decision to block changes to an EU treaty was "the right thing for Britain" as it "didn't have sufficient safeguards for Britain".
Cameron will face MPs on Monday when he delivers a statement to the Commons.