Liz Truss' own Home Secretary has said her approach "clearly wasn't" the right one, and she failed to take account of "reality".
Business Secretary Grant Shapps was brought in to run the Home Office for a few days between Suella Braverman being sacked and the PM quitting.
It comes as failed Prime Minister made a "deranged" bid to return to frontline politics, having nearly crashed the economy in just 49-days in office.
In a 4,000 word screed for the Telegraph, Ms Truss blamed everyone from the "economic establishment" to Joe Biden for getting in the way of her bonkers plan for unfunded tax cuts.
A Tory source told the Mirror: "She’s more deranged than we realised.
"This is the woman who almost caused a run on the pound and is now pretending she has some answer to our problems.
"She should stick to the after dinner speaker circuit, cashing in on why she was the worst prime minister in uk history."
And while defending the idea of a "low tax economy", when asked if Ms Truss' approach had been the right one Mr Shapps told the BBC's Laura Kuenssberg: "Well, clearly it wasn't."
And he indicated the former PM had failed to take account of "reality."
He added: "I think she's right about the need for long-term lower tax, but it rubs up against the reality of two or three years of Covid, and £400 billion cost of that.
"Followed by a war and the enormous cost of inflation."
He added: "While I agree with the desire to see a lower tax economy, I think first you have to put the building blocks in place."
Earlier, Shadow business secretary Jonathan Reynolds told Sky's Sophy Ridge On Sunday: "Will there ever be a Conservative willing to take responsibility for their own actions?
" Liz Truss had to stand down because her policies were incoherent and unsustainable and the idea she's been brought down by a left-wing economic establishment - she's been brought down by straightforward economics."
But former Tory chair and Truss-ally Jake Berry said: "I still agree with Liz's diagnosis of the disease that is facing the country and I think she accepts in this story that the prescription that we wrote - which I have to take part of the blame - wasn't delivered in the correct way.
"But I think her point of we need to lower taxes, we need to create a growing economy, that's what people want."
