Labour has called for Jacob Rees-Mogg to quit as Commons leader over the Owen Paterson sleaze row.
Shadow leader of the Commons Thangam Debbonaire said Mr Rees-Mogg's position has become "untenable" because he has lost control.
Mr Rees-Mogg made an embarrassing u-turn on Thursday, scrapping plans to rip up ethics rules in order to save Owen Paterson from a 30-day suspension.
Boris Johnson had ordered Tory MPs to vote to block the suspension Mr Paterson from the Commons for lobbying on behalf of two firms - and to create a new Tory-led panel to review his case.
But the plans triggered a furious outcry and were immediately plunged into chaos when Labour, the SNP and Liberal Democrats vowed to boycott the new committee.
Ms Debbonaire slammed the Government, including Mr Rees-Mogg, for “conflating” the Paterson case with attempts to overhaul the standards watchdog.
She told Sky News' Trevor Philips on Sunday: “This is Tory sleaze, pure and simple.”
And pressed on whether Mr Rees-Mogg should resign, Ms Debbonaire added: “If I was him, I’d be considering my position, that’s what I think he should do today.”
She added: “I think his position is untenable."
Commons Leader Mr Rees-Mogg told MPs that he would seek cross party changes to the system as the plan did not have support.
Environment Secretary George Eustice dismissed the Owen Paterson affair as a “storm in a teacup”.
He acknowledged the Government had “made a mistake” in trying to get Mr Paterson’s breach of lobbying rules re-examined by a new Tory-majority committee which would also consider the entire Commons standards regime.
But Labour MP Jess Philips responded to his comments on Twitter slamming Mr Eustice as a liar.
She tweeted: "George Eustice is just lying. Everything he is saying is just a lie.
"Owen Paterson did have a chance to defend himself and did so throughout. The motion was about Paterson not just a new process. Lie after lie."
The back-tracking came only hours after Cabinet Minister Kwasi Kwarteng was sent out on the airwaves to defend the plan, when he insisted he felt no shame over the controversial overhaul.
Former Tory cabinet minister David Mellor criticised Mr Kwarteng for suggesting the future of Parliamentary Commissioner for Standards Kathryn Stone was in doubt.
Mr Mellor told Sky News: “He was doing it because he thought that would please Boris and a lot of them – it’s like a children’s party – they all want to please daddy, but the reality is a cabinet minister should be above and beyond that.”
And he claimed the PM's disregard for rules will get him into trouble in the long run.
“I think it’s astonishing the Prime Minister has allowed himself to get into this muddle over Owen Paterson," Mr Mellor added.
Mr Mellor added to Trevor Phillips on Sunday on Sky News: “The Prime Minister has many great strengths but he doesn’t seem to respect the rules – and he himself gets himself into trouble with these rules, and the fact he doesn’t believe in rules will count against him in the long run.”
