Cabinet minister Iain Duncan Smith has denied threatening to quit the Cabinet if he was asked again to vote against a referendum on Europe.
The Work and Pensions Secretary insisted that, contrary to rumours, he had not wanted to vote for Monday's motion proposing an in-out referendum on British membership of the European Union.
There have been reports that the staunch eurosceptic had a stand-up row with government Chief Whip Patrick McLoughlin over the imposition of a three-line whip requiring ministers to vote against the referendum.
He is said to have told Mr McLoughlin: "If you ever put me in this position again, that's it."
But, speaking on BBC One's Question Time, Mr Duncan Smith said that was "Chinese whispers", adding: "I haven't had that kind of conversation with the Chief Whip but that shouldn't stop the press having a good time with it."
Asked whether he had objected to the three-line whip - which was defied by 81 Tory MPs including two ministerial aides - he said he was "not really going to get caught up in that".
The Maastricht rebel rejected the suggestion that he had put ambition ahead of integrity by voting against the motion.
"No, I don't have an ambition - I came into government for one reason and one reason only, which is to try and reform welfare and change society, that is my purpose for being here," he said.
Mr Duncan Smith insisted that his position was that "it was not the right motion" on Monday.
"We believe that there does need to be a readjustment of that relationship but the question in front of us on Monday was very simple - do you think that this motion was the right motion to put to the British public? The answer is no, I do not think that was the case."