Prime Minister Gordon Brown comfortably saw off a Tory attempt to force a referendum on the European Union's controversial Lisbon Treaty.
A Conservative amendment calling for a referendum was defeated by 311 votes to 248 - a majority of 63 - as just 29 Labour rebels joined the Tories in the division lobbies. A rebel Labour amendment was defeated by a similar margin of 311 to 247.
However Nick Clegg's leadership of the Liberal Democrats was left in disarray as a total of 15 Lib Dem MPs - almost a quarter of the parliamentary party - defied orders to abstain and voted instead for a referendum.
Three senior frontbenchers - justice spokesman David Heath, countryside spokesman Tim Farron, and Scotland and Northern Ireland spokesman Alistair Carmichael - quit to join the revolt.
Mr Clegg, who has been leader for less than three months, denied that he had made a massive miscalculation in imposing a three line whip, insisting that he had the support of "overwhelming majority" of Lib Dem MPs.
"These things happen on issues with the importance of Europe," he told Channel 4 News. "It is not such a big thing that from time to time in a parliamentary party there is a division of opinion."
He said that he would be speaking to other rebels - including eight junior frontbenchers - in the coming "hours and days" but appeared to rule out further sackings.
"Do I reassert my authority by having some great cull? This is not the way that politics works. I will make sure - have made sure - that there is discipline in the overwhelming majority of the parliamentary party," he said.
However the scale of the rebellion left him with little room to manoeuvre. None of the three MPs who quit will be replaced. Instead, their responsibilities were simply reassigned to other members of the frontbench team.
Nevertheless, Lib Dem MPs were left asking how their party - for long seen as the most united on Europe - came out of the voting looking the most divided.
Mr Clegg had hoped to overcome the differences by calling for a referendum on the whole issue of Britain's continued membership of the EU, rather than on the narrower issue of the treaty.
Like the Government, the Lib Dem leadership argued that a referendum on the treaty was not necessary as it is a very different document from now abandoned EU constitution, which all three main parties has promised to put to a referendum.
However, Mr Carmichael said that he could not accept that argument.
"I have no doubt that in reaching this view they have all acted in good faith and all sincerity. It is, however, a judgment which I am unable to share," he said.
Mr Clegg will now be under pressure to re-assert his authority when he delivers his first big setpiece speech as party leader at the Lib Dems' spring conference in Liverpool at the weekend.
Labour rebel Kate Hoey said that for her and her colleagues it had come down to a simple issue of trust.
"You don't go on a big issue like this and tell the electorate what you are going to do and then, for other reasons, simply turn round and say we are not going to vote," she told Sky News.
Shadow foreign secretary William Hague said that the Conservatives would now attempt to reintroduce the referendum amendment when the treaty goes to the House of Lords.
"It is convention that the House of Lords does not stand in the way of manifesto commitments. We hope that in this case the Lords will hold the Government to their manifesto commitment," he said.
"The Liberal Democrats' position will once again be pivotal. We will see if they follow their three line whip in the Commons to abstain."
Derek Scott, the former Downing Street economics adviser who now chairs the I Want a Referendum campaign, said the parliamentary arithmetic could work in their favour in the upper chamber where the Government has no overall majority.
"The battle now moves on to the Lords where the pro-referendum campaign has a better chance of winning," he said.
"If Nick Clegg keeps his promise to make Liberal Democrat peers abstain then there is every chance that the Lords will vote for a referendum."