The rebellion strengthened as the Prime Minister refused to rule out a real-terms cuts to benefits, with Commons Leader Penny Mourdant instead insisting the welfare payments should be increased to match inflation.
Home secretary Suella Braverman then conceded she was “disappointed” by Chancellor Kwasi Kwarteng and Ms Truss’s mid-conference tax U-turn, and accused Tory rebels like former Cabinet minister Michael Gove of staging a “coup”.
It was yet another day of bitter infighting and gaffes at the Conservative Party conference in Birmingham on Tuesday, with Mr Kwarteng suggesting he would bring forward his medium-term fiscal plan, only to then rule it out.
Ms Truss now faces an uphill battle to keep her party together and restore discipline, with her former supporter Nadine Dorries again demanding a general election.
Just four weeks into her premiership, Ms Truss will make the most important speech of her career on Wednesday, hoping to take back the narrative from what one MP described as a “car crash conference”.
Speaking before midday on Wednesday, Ms Truss will defend her “new approach” and claim it will “unleash the full potential of our great country”.
She will tell activists in Birmingham she hopes to create a “new Britain for a new era”, with an unashamedly pro-growth agenda – even though not everyone will be in favour of her methods.
It will come against the backdrop of many MPs and staffers heading home on Tuesday rather than staying for her speech, which is scheduled amidst rail strikes, and with a fresh YouGov poll finding the UK Government has an 11 per cent approval rating.
Ms Mordaunt joined backbench rebels in calling for welfare payments to be raised in line with inflation, which has been at around 10 per cent, rather than earnings at 5 per cent.
She said: “I’ve always supported, whether it’s pensions, whether it’s our welfare system, keeping pace with inflation. It makes sense to do so.
"That’s what I voted for before and so have a lot of my colleagues”.
This prompted Ms Truss to be asked whether the Commons Leader had to be sacked questions to enforce discipline in her ranks.
She told ITV News: “No, she doesn’t. This is about a decision that we are taking later on this year.”
The Prime Minister scrapped her plans for a tax cut for the wealthiest on Monday, saying it had become a “distraction” as senior Tories threatened to vote against it in the Commons.
However, on Tuesday she revealed the initiative could come back, with the plans not completely dead.
She told the BBC: “I would like to see the higher rate lower. I want us to be a competitive country, but I have listened to feedback. I want to take people with me.
“I’m not contemplating that now, I’m very, very clear that we’ve listened to people about what their priorities are.”
At the same time, her home secretary vented her frustration at the U-turn, hitting out at former Cabinet ministers who criticised it.
Ms Braverman said: "I’m disappointed about the subsequent reversal, but I accept their reasons.
“Ultimately I’m very disappointed that members of our own party staged a coup, effectively, against the Prime Minister.
“I’m very disappointed to say the least by how some of our colleagues have behaved.”
She said former minister Mr Gove “got it wrong”, stressing it was “incumbent on him to try and corral support” for Ms Truss and he should have raised his concerns “in private”.
Her comments leave her supporting a Government policy already dropped, and deepen the rift between ministers and some sections of the party.
Levelling-up secretary Simon Clarke, one of Ms Truss’s closest allies, backed Ms Braverman’s comments, saying she “speaks a lot of good sense, as usual”.
Elsewhere, there was yet another hint of a U-turn after Mr Kwarteng told the conference he would publish his fiscal plan and Office for Budget Responsibility forecasts “shortly”.
The Chancellor had previously promised to publish them on November 23, but Tuesday saw his allies brief this could now happen earlier.
However, Ms Truss then told GB News the original date still stood, opposing briefings being made by members of her own Government.
Downing Street aides said only the PM may consider bringing the date forward, downgrading the likelihood of the move.
In a separate interview, Mr Kwarteng then denied he was changing his plan, saying “shortly is the 23rd” and accusing people of “reading the runes” incorrectly.
The scale of conflict within the party led former transport secretary Grant Shapps to warn Ms Truss had ten days to save her premiership.
He told The News Agents podcast: “The next ten days is a critical period of time. She’s got a conference speech to make after a very difficult few days, she’s got the MPs coming back together again for the first time since things became choppy – of course, I mean, it’d be ludicrous to say anything else.
“But is it possible? Yes, it is possible, and I’m cheering her on to do it.”
Speaking to Times Radio, Mr Shapps added: “Obviously, the policies are critically important, not making these errors. So I think it could have been different.
"I don't think it's, you know, game over. I am cheering her on to succeed. Let's see how she does.”
He suggested some Tory MPs at risk of losing their seats in a general election might consider replacing her with a new leader.
Mr Shapps added: “The question is for Conservative MPs, if they are in any case thinking ‘well, I’m going to be out at the next election’, then they might as well roll the dice, as it were, and elect a new leader.”
In delivering a conference speech critical to her immediate future, Ms Truss will say: “For too long, our economy has not grown as strongly as it should have done.
“For too long, the political debate has been dominated by how we distribute a limited economic pie. Instead, we need to grow the pie so that everyone gets a bigger slice.
“That is why I am determined to take a new approach and break us out of this high-tax, low-growth cycle. That is what our plan is about – getting our economy growing and rebuilding Britain through reform.”
Alongside measures to boost growth, the Prime Minister will insist she will keep an iron grip on the nation’s finances, with a leaner state offering value for taxpayers’ money.
She will say: “This is a great country. But I know that we can do better and we must do better.
“We have huge talent across the country. We’re not making enough of it. To deliver this, we need to get Britain moving. We cannot have any more drift and delay at this vital time.”
Naomi Smith, chief executive of cross-party campaign group Best for Britain, said: “After being selected by a tiny group of Tory Party members and crashing the economy within weeks of taking office, it is a democratic outrage that Truss can continue to squat in Number 10 without going to the people.
“It is blindingly obvious that the Tories need a long spell in opposition. Labour should commit to reforming our broken electoral system to ensure that no party can wield total unaccountable power again with a minority of votes.”