Graham Brady reveals secrets about the ousting of five Tory prime ministers

However, Lord Brady writes: “A rumour spread that Rishi had called the election because I had told him that he would have to face a vote of confidence. I had given no such indication. As we set off towards the smoke of battle, there were 10 letters in my safe.”

Even before the local elections in May, the knife was drawn against Mr Sunak when Lord Brady claimed that Ms Mordaunt had tried to replace him early on.

Revealing that a rumour had emerged that “Rishi would simply resign” if the results were bad, he writes: “At a meeting with me shortly afterwards, Leader of the House of Commons Penny Mordaunt said: 'I wouldn't ask you… but if something were to happen… if Rishi were to resign after the local elections, I hope there is a plan for a quiet transition.'”

On 22 May, Mr Sunak personally telephoned Lord Brady to inform him that he would call the 4 July election that afternoon – to the shock and dismay of his Conservative colleagues, who then called an emergency meeting of the 1922 Committee.

Dame Andrea Leadsom, then Health Secretary, is reported to have asked Lord Brady: “If enough of us send you letters calling for a vote of no confidence, can we stop the Prime Minister from leading the Conservative Party to ruin?”

Like many Tories, Lord Brady – who was a vocal member of the lockdown-sceptic Covid Recovery Group of Conservative MPs – has repeatedly clashed with Boris Johnson over his “draconian” approach to the pandemic.

Mr Johnson was apparently so angered by Tories' criticism of Mr Cummings over his lockdown-breaking trip to Bernard Castle in 2020 that he angrily labelled them “cowardly cowards”, although he said Mr Cummings was “not in his right mind”.

Echoing Cummings' description of his former boss as a “shopping trolley” during the pandemic, Lord Brady claimed Johnson railed against the “bloody stupid two-metre rule” and “bloody scientists” while telling those who questioned his Covid measures: “How many people would you let die?”

He refused to resign until the night before his resignation in 2022, telling Lord Brady: “You would be mad to get rid of a leader who has won the largest Conservative majority since 1987.”

The fraud was so extensive that Mrs Truss initially blamed Kwasi Kwarteng for the disastrous 2022 mini-budget and replaced him with Mr Hunt, before the new Chancellor of the Exchequer, Lord Brady, told her she “had to go”.

Six days later, Ms Truss resigned after a brief conversation with Lord Brady, who was then forced to “hide” in 10 Downing Street until her statement to avoid the press mob gathered outside.

Lord Brady, a former MP for Altrincham and Sale who resigned from Lord Cameron's shadow cabinet in 2007 over his opposition to grammar schools, accused the former prime minister of an “act of petulance” when he resigned the day after the 2016 EU referendum.

He argued that the conduct of Lord Cameron and his Chancellor of the Exchequer, Mr Osborne, had been “unprincipled both in the run-up to the election campaign and during it…”.

Amid a series of scandals in 2014, he reveals that the former Eton student once told him: “The fact is that a lot of politics is just shit: it's about choosing the least bad option… Life would be easier if colleagues paid their expenses on time. [sic] and didn't snort coke or anal abuse each other.”