Conservatives have accused Chief Whip Andrew Mitchell of "reigniting" the row over his alleged "pleb" outburst by denying swearing at police during Prime Minister's Question Time.
In a series of messages on Twitter, Tory MP Michael Fabricant attacked Mitchell's behaviour.
Mitchell has always made clear that he disputes the words attributed to him in press reports of the police record of the incident, but has not explained precisely what he does recall saying.
At the weekly meeting of the Conservative backbench 1922 Committee at Westminster, four Tory MPs were said to have robustly criticised Mitchell staying in post in wake of the allegations.
Those speaking out against Mitchell are reported to have included Tory MPs Anne Main, Sarah Wollaston and Andrew Percy.
But sources said they were outnumbered by up to 15 defenders of Mitchell, led by Tory grandees Sir Peter Tapsell and Bernard Jenkin, with supporters of Mitchell saying it would be "a spectacular own goal" were he forced to go now.
Senior sources acknowledged that the whole affair had been damaging for him.
"The sense is he will need to rebuild relationships," one source said. "You don't come through something like this emboldened."
Overall, however, the mood was said to be that it had "gone on long enough" and it was time to draw a line under the matter.
The discussion about Mitchell lasted around 30 minutes - leaving Chancellor George Osborne, who was the main speaker, to wait outside in the corridor before he was able to address them.