The confrontation between fiercely anti-gay marriage MP Sir Gerald Howarth and rising star Gavin Barwell took place in front of shocked colleagues in the Commons Tea Room.
One onlooker told The Mail on Sunday that ‘offensive words relating to sexual orientation’ were used – although this aspect of the exchange is denied by the men.
At the meeting on Tuesday, the MPs warned Mr Cameron the party was haemorrhaging support over the issue. Northampton MP Brian Binley told him: ‘The problem is, you are not listening to your core vote.’
No 10 did not confirm Mr Cameron’s comments last night.
More than 100 Tory MPs are expected to rebel when the issue comes to a Commons vote, expected at the end of next month.
Prime Minister David Cameron has been warned he risks tearing the Conservative party apart with his plan to legalise gay marriageOpponents of the measure claim Mr Cameron’s party Whips are using ‘dirty tricks’ in an attempt to avert an embarrassing defeat.
One said: ‘Even though it is supposed to be a free vote, there are suggestions the Whips are telling MPs known to support gay marriage that they must be present but allowing those against to stay away if they wish. I’ve been told that there is a parliamentary trip where one pro-MP is being told he must come back, while an opponent is under no such instruction.’
The stormy confrontation between Mr Barwell and Sir Gerald took place earlier this week.
One witness said: ‘It was pretty toxic. Howarth was being critical of Barwell’s support for the measure, and Barwell gave as good as he got.’
Last night, Aldershot MP Sir Gerald confirmed that he had a ‘robust’ argument with Mr Barwell. He also acknowledged he was ‘angry’ about the gay marriage Bill, branding it a ‘catastrophe’.
However, the former Defence Minister denied using homophobic language. He said: ‘Gavin and I had a discussion. This issue is deeply divisive. It’s pitting friend against friend.’
Croydon MP Mr Barwell, who is an aide to Education Secretary Michael Gove – a key Cabinet supporter of same-sex marriage – said he had a ‘free and frank’ discussion with Sir Gerald. He declined to characterise it as a row or to discuss the terminology used.
However, his Tory colleague Alec Shelbrooke said: ‘I’ve heard Gerald had an argument with Gavin in the Tea Room. We have been told it was very nasty.’
Last night, there were claims the Prime Minister had finally realised the depth of anger over the issue.
Tory MPs said they had been invited to a meeting with Mr Cameron as soon as the Commons resumes in the New Year that will ‘focus’ on the 2015 General Election campaign.