The UK economy fared better than previously thought during the year that Liz Truss delivered the mini-budget. Photo: Victoria Jones/PA/ PA Wire

A new biography of the former prime minister by Sir Anthony Seldon makes the extraordinary claim that in the immediate aftermath of the mini-Budget, Ms Truss and her chancellor Kwasi Kwarteng launched a desperate attempt to find spending cuts in an effort to restore stock-market confidence in their strategy.

Sir Anthony said a group of the prime minister’s aides met to discuss the issue. One of her senior advisers, Alex Boyd, “was told that Truss and Kwarteng were thinking they could still sort out the black hole with severe cuts”: “We’ve been told that they’re looking at stopping cancer treatment on the NHS.”

In response, Mr Boyd asked “Is she being serious?” writes Sir Anthony, while other aides said she had “lost the plot”.

“She’s shouting at everyone that ‘We’ve got to find the money.’ When we tell her it can’t be done, she shouts back: ‘It’s not true. The money is there. You go and find it,’” they told the author.

But a spokesperson for Ms Truss said it was “completely untrue that she ever considered” cutting cancer treatment.

Meanwhile, her chancellor Kwasi Kwarteng, who was also said to have been involved, told The Independent: “I wasn’t involved in any conversations about restricting healthcare, but that doesn’t mean the prime minister and her team didn’t discuss this.”

Sir Anthony’s book, Truss at 10: How Not to Be a Prime Minister, is deeply critical of Ms Truss, who was forced to resign in 2022 just 49 days into her premiership after she triggered an economic crisis by proposing the introduction of £45bn of unfunded tax cuts.

Sir Anthony, who is Britain’s leading political biographer, also claimed Ms Truss’s allies were concerned her team could be targeted with a “cocaine” smear by unnamed figures at Tory HQ who wanted to stop her from becoming prime minister.

He said the former prime minister suspected a “dirty tricks” operation was being planned by unnamed figures in Tory HQ as part of an attempt to prevent her from becoming leader of the party, with allies fearing there may be an attempt to “intimidate her with talk of a thick dossier of her indiscretions, her drinking, cocaine use by others among her team”. But the dossier “never materialised”, the author said.