Inside seven days, she has been forced to fire her first-choice chancellor Kwasi Kwarteng, architect of a disgraced and replaced mini-budget, and her Home Secretary Suella Bravelerman has quit over a security breach but also citing the "direction of this government".
Normally, the 1922 Committee of backbench Conservative MPs allows her — as the newly-elected party leader — a year without a challenge to her leadership. But the committee has the power to change its own rules and there are ways she can be forced out.
Truss could resign
She could step down — sparking a new election for party leader and prime minister — but so far she has shown no signs of giving way to the pressure.
It would be the simplest way for Ms Truss to leave office but there are no hints it will happen as she has said she wants to lead the Conservative Party into the next general election.
She said she still wants to speed up Britain’s growth but accepts the discredited budget is not the way to do it.
“I remain committed to the vision, but we will have to deliver that in a different way,” she said.
She added that the budget went “too far, too fast” and that she wanted to “say sorry for the mistakes that have been made”.
“I do think it is the mark of an honest politician who does say ‘yes, I've made a mistake. I've addressed that mistake. And now we need to deliver for people'.
“It would have been completely irresponsible for me not to act in the national interest in the way I have.”
If members of her Cabinet start resigning that could be a sign that she has lost their confidence and it could force her to follow, echoing the way Boris Johnson left office.
The 1992 Committee
In “normal” times, the 1922 Committee gives a new party leader a year's grace, with no possibility of a leadership challenge.
But after the budget U-turn and surrounding chaos, MPs are angry. Five have publicly called for Ms Truss to quit.
To force her out, the Committee would have to change the rules — but that is something they have done before.
A vote of no confidence from her own MPs could force the prime minister out of office.
Under the existing rules, 15 per cent of the 356 Conservative MPs would need to write a letter requesting a confidence vote.
MPs could write to committee Chairman Sir Graham Brady expressing a lack of confidence and demanding the rules are changed.
In that scenario, he may then tell the prime minster about the rebellion, a move that could persuade her to resign.
Sir Charles Walker MP was one of the first to call for Ms Truss’s exit.
“I think her position is untenable. She has put colleagues, the country, through a huge amount of unnecessary pain and upset and worry,” he said.
The situation “can only be remedied” with a new prime minister, he said.
If Ms Truss refuses to resign, and loses a confidence vote among her own MPs, she would be ousted and a new leader could be appointed without the need for a general election.
Two new backbenchers will be elected to the 1922 executive on Tuesday and they could bring with them the impetus for rule changes.
If Tory MPs cannot force Ms Truss out, they could join forces with opposition parties in a parliamentary vote of no confidence.
If she were to lose that — a vote among all MPs — the government would also fall and a general election would have to be called.
The latest opinion polls show Ms Truss has just 10 per cent support among the public and is the most unpopular leader in 20 years.
More importantly, the party has also fallen dramatically in opinion polls — with Labour 36 points ahead.
So if Ms Truss was removed by a no-confidence vote in parliament, a general election would be triggered that the Conservatives would be favourites to lose.