Mr Cameron proposes that ministers can vote on the 1922 Committee
David Cameron's proposal to open up the Conservatives' powerful backbench committee to ministers has been voted through - despite strong opposition.
Tory MPs voted by 168 to 118 in favour of changes which are expected to allow ministers a vote at the 1922 Committee.
Mr Cameron said he was not "picking a fight" and he felt "bringing the party together was the right thing to do".
But some Tory MPs, who were only told of the plan last night, were angry and said it came as "a bolt from the blue".
BBC Political Correspondent Ross Hawkins said Mr Cameron may have weakened a potentially hostile committee, but had also "stoked the resentment of those who could make his life difficult in the future", given that the coalition rests on the prime minister's ability to command the confidence of the House.
He said some Tory backbenchers were "spitting nails" over the move and there was talk of legal challenges or setting up another committee.
Membership of the 1922 Committee is usually restricted to backbench MPs when the party is in government. It is usually separate from the party leadership and keeps it informed about the mood on the back benches.
But on Wednesday, Mr Cameron proposed changing the rules. MPs voted in favour of his proposal that "the 1922 Committee should change to encompass the whole of the parliamentary party".
The announcement could mean ministers would be able to vote in the election of the 1922 Committee chairman on 26 May. It was made to the surprise and annoyance of some Tory MPs, some of whom were already unhappy about aspects of the coalition deal with the Liberal Democrats.
Mr Cameron insisted he was not "picking a fight with anyone" adding: "I profoundly believe that having a single party meeting, bringing the party together, is the right thing to do.
"And I believe in leading from the front. If you think something is right to do, don't wait for it to be proved a few months into the government, when backbench and frontbench aren't talking to each other properly, get on and do it, and ask the party to make that change. That's the decision I took."
The committee, which takes its name from the year in which its founders were elected, meets each week to discuss parliamentary business and take grievances to the Conservative leadership.
A Conservative official insisted the move would merely mean the committee continued to operate the same way as it had while the party was in opposition - when frontbenchers could vote and speak at meetings.
But backbench MP Christopher Chope said the plan "could have implications for example when we come to vote for membership of select committees because select committees are the opportunity for backbenchers to hold the government to account".
He wrote to all Tory MPs on Wednesday pointing out that the 1922 Committee had ruled unanimously in March that only backbenchers should be able to elect the chairman and officers of the committee and at the time, the Tory leadership raised no objection.
And his Conservative colleague Peter Bone said: "We had no notice of this, there was no debate and the vote took place hours after it was announced, no trade union in the country would be allowed to get away with that practice."
He said it was "fundamentally wrong" because the new Conservative MPs would not "understand the issues" and had not "been given any chance to hear the views of different people on this".
Backbench MP Bill Cash also complained there had been no discussion about the move before it happened. He told the BBC on Wednesday evening "I heard about it, candidates for the chairman of the 1922 Committee only heard about it, ten minutes before the meeting."
He said he thought the move was "a great tragedy" as Tory MPs wished the new government well. But he said the move, along with a "tsunami of changes taking place" - a reference to concessions to the Liberal Democrats in the coalition deal - could "create a great deal of uncertainty and tension".
But Chancellor George Osborne told BBC Radio 4's World At One programme: "The idea is this, that we behave and act as a single party, front bench and back bench."
He said the new Conservative MPs he had seen were "very enthusiastic about what lies ahead" - about strong, stable government to "improve our country for the better".
It is understood that the two MPs hoping to become the committee's chairman - Graham Brady and Richard Ottaway - only found out about the plan shortly before the meeting.
In an article for The Spectator, due to be published on 22 May, Mr Brady says: "A majority government can largely presume the consent of its MPs... A coalition government cannot."