She reveals that she was given the “starkest of warnings” by senior officials that any further economic turbulence could leave the UK unable to fund its own debt.
Ms Truss sacked Kwasi Kwarteng, her chancellor, and less than a week later resigned as prime minister, saying she no longer commanded the confidence of her MPs.
“I still believe that seeking to deliver the original policy prescription on which I had fought the leadership election was the right thing to do,” she writes. “But the forces against it were too great.”
“I am not claiming to be blameless in what happened, but fundamentally I was not given a realistic chance to enact my policies by a very powerful economic establishment, coupled with a lack of political support,” she says.
She recalls entering office presuming her “mandate would be respected and accepted”.
“How wrong I was,” she writes.
She condemns “endemic” levels of “pessimism and scepticism” at the Treasury about the potential for growth in the British economy.
And in a damning indictment of the department, she reveals that in the run-up to the mini-Budget, no one there highlighted any risks to pension funds – which would trigger unprecedented volatility in the gilt market – to either her or Mr Kwarteng.
“At no point during any of the preparations for the mini-Budget had any concerns about Liability-Driven Investments (LDIs) and the risk they posed to bond markets been mentioned at all to me, the Chancellor or any of our teams by officials at the Treasury,” she says.
This was a significant omission, she argues, because this issue “would ultimately bring my premiership to an abrupt and premature end because of the panic it induced”.
“Only now can I appreciate what a delicate tinderbox we were dealing with in respect of the LDIs,” she adds.
Ms Truss says her mini-Budget was made a “scapegoat” for problems that had been “brewing” for a number of months including rising interest rates and mortgage costs, which had already been forecast to go up.