By Alex Stevenson Follow @alex__stevenson
Liberal Democrats have refused to back the government over a Commons motion praising David Cameron's EU treaty veto.
The coalition's junior party ratcheted up tensions in Whitehall by abstaining en masse in the vote which ended last night's debate on the use of the British veto.
Lib Dem MPs refused to back a Democratic Unionist party motion which commended the prime minister for refusing to sign up to the fiscal integration treaty agreed by other EU members and called for a "rebalancing of the relationship with our European neighbours".
The motion was passed by 278 votes to 200 despite the absence of Lib Dem MPs.
Only one Lib Dem spoke in the debate - the party's backbench spokesperson on foreign affairs issues, Martin Horwood.
He said that the argument about repatriating powers, a key goal of Conservative eurosceptics, "completely misses the point" and instead called for Tories and Lib Dems to come together.
"Conservatives and Liberal Democrats should unite on a reform agenda in Europe which does not necessarily require treaty change but will, I hope, be supported by other countries," Mr Horwood said.
"Then we can build alliances and go forward positively, with the like-minded countries of Europe putting forward a positive and good plan for British jobs and British prosperity, for European jobs and European prosperity."
Nigel Dodds, the DUP MP who led the debate, pointed out that there was already significant support for the prime minister's approach.
"It is clear that a large number of people from all backgrounds, whether they are Tory, Labour, Liberal Democrat or support parties in Northern Ireland, agree with what the prime minister has done," he suggested.
The absence of Lib Dems from the voting lobbies did not go unnoticed. Labour veteran backbencher John Spellar raised a point of order in which he observed: "We live in some fairly interesting times, because not only do we have a deputy prime minister who has gone missing, but I am reliably informed that not one Liberal Democrat member voted in the lobby to support the prime minister. Is there a precedent for that within a government?"
The Speaker observed that Mr Spellar was a "wise greybeard" and that "there are precedents for most things", before ruling that Liberal Democrat voting habits were not one for the chair.