I have to start this review by declaring an interest. As a former Conservative MP, expelled from the party for standing as an independent in 2019, I had, apart from that election, never campaigned against a Conservative candidate. In June this year, however, I made the decision to support the independent James Bagge (another former Conservative), who stood against Liz Truss in South West Norfolk. His intervention, as a former member of her Conservative Association, helped overturn one of the largest Conservative majorities in the country – he secured more than 6,000 votes. My reason for doing this was that I thought it wrong for a former prime minister who had done so much damage, albeit unintentionally, to our country’s economic wellbeing and reputation to stand again. As was clear on the ground during the campaign and in its outcome, this was also the view of her constituents.

Anthony Seldon, now with the help of Jonathan Meakin, has become the leading authority on our contemporary prime ministers and the challenges they face in office. So, it was natural that after last year’s Johnson at 10, he would want to consider Truss. The problem, however, is that 49 days provides rather thin material for a book, as does any account of the steps that got her there. Truss’s personal background and prior political career are covered quickly, in about 12 pages out of 330. Seldon identifies her core belief as being free market liberalism with a deep suspicion of entrenched vested interests. He sees her as an autodidact. He says that “Truss zipped up the ministerial ladder. But she never felt particularly successful on the rungs, nor was she to win many admirers for her pirouettes as she reached the top.”

As a former colleague, I think this encapsulates well how she was viewed within the parliamentary party under Cameron and May. Whether it was her speech to party conference on the “DISGRACE” of importing apples, pears and cheese, or her failure, as lord chancellor, to defend the judiciary when they were attacked in the media as “enemies of the people”, she was not seen as a political heavyweight, or taken seriously by most Conservative MPs. Seldon is kinder on her period as foreign secretary, where he sees her as having shown considerable acumen in establishing a reputation as an international crusader for liberty. But this was accompanied by an almost obsessional self-regard, with every overseas trip turned into a photo opportunity.

Seldon has therefore chosen to turn her short period in office into a textbook of how not to govern, a sort of reverse of Machiavelli’s The Prince. In previous work, he has outlined a number of steps he believes are key to a prime minister’s success. He compares her performance with each such requirement and finds it wanting in every case. Thus on the need to “secure the power base” he shows how her campaign for the leadership, while skilful, was based on an appeal to the party membership, still grieving at the loss of Boris Johnson and attracted by his endorsement, as well as her own promises of tax cuts. It left those MPs who had had the courage to vote to get rid of Johnson for overwhelmingly good reasons “sceptical, cynical and even angry” – a bad way to start a premiership where she needed to build their support.

Seldon rightly sees Truss as having had a bold plan for government, but it was never realistic. Her decisions were the product of “self-reinforcing groupthink, as confidence and daring led to arrogance and, ultimately, hubris”. She packed her cabinet with a narrow group of supporters. A member of her team tells Seldon that she said: “I have beaten my enemies, I have beaten the fucking establishment. I’m not going to bother to build bridges.” Yet for all this bravado, she struck an anonymous figure when big events such as the death of Queen Elizabeth gave her the opportunity to present herself as a stateswoman. Seldon notes that, as a committed Atlanticist, she utterly mishandled relations with President Joe Biden, prompting what he describes as the most humiliating presidential put down of a prime minister in modern history, when he openly described her economic policies to journalists as a mistake.

Truss’s downfall was the result of the big policy failure of her mini budget, the resulting loss of any reputation for economic competence, a humiliating U-turn in having to appoint Jeremy Hunt chancellor and ditch her plans for growth, and the resulting collapse in confidence – such as it was – among her MPs. Seldon writes very well on this. His research has been extensive and the commentary is fleshed out with dialogue and quotations, which he assures us have been checked for accuracy and make for compelling reading. His verdict is harsh. “Britain has had a procession of underperforming Prime Ministers … Johnson, the subject of the previous book in the series, and now Truss, comfortably outdid them all in their wilful inability to rise to the requirement of thoughtful and responsible stewardship the job entails”.

As I write this, news comes in of Truss’s talk in Beccles, Suffolk, where promotion of her book Ten Years to Save the West was interrupted by the unfurling of a poster of a cross-eyed lettuce with the caption “I crashed the economy”. Other politicians might have turned an incident like this to their advantage. She simply walked off, saying: “That’s not funny”. I would add to Seldon’s requirements for prime ministers the need for a self-deprecatory sense of humour.