Did you know that, before the development of modern tests in the middle of the 20th century, Britain’s National Health Service used to check whether a woman was pregnant by injecting a toad with her urine? I confess that I didn’t. Sadly, it was just about the only truly arresting thing I learnt from reading Theresa May’s new book.

May’s book is not, for the most part, an autobiography or even a first-hand, blow-by-blow, tell-all account of her rise to political prominence, first as home secretary in David Cameron’s Cabinet and then as prime minister following Cameron’s resignation in the wake of the UK voting to leave the EU in 2016. For a thorough study of May’s political career, readers will need to turn either to Anthony Seldon’s May at 10 or to Rosa Prince’s arguably mistitled Theresa May: The Enigmatic Prime Minister, although the latter needs updating to take account of its subject’s fall from power in 2019.

Instead, May’s book is a series of case studies of scandals which she was apparently able to use her position in order to bring to light. In many cases she claims to have achieved some measure of justice for those involved. Consequently, her book risks being seen as not so much a genuine crusade against what she still likes to refer to as ‘burning injustices’ as an extended humblebrag by a politician who feels both underestimated and unappreciated.

Each of the scandals, according to May (who provides a fairly prosaic precis of all of them), was rooted in the systemic abuse of power by politicians, civil servants and the police. Occasionally commercial interests are afforded a measure of criticism. But – as befits a Conservative politician who, judging from the odd reference to privatisation, still seems to think that flogging off the UK’s utilities has made them more responsive to consumers – by far the majority of the blame is ascribed to the state. In May’s mind (and it is a point rather monotonously made in the final paragraph of virtually every chapter), its agents abused the power with which they were entrusted, and/or allowed others to do so, ‘because they could’.

If that reminds some readers of an old and not particularly savoury joke about dogs and their private parts, I can only apologise. Perhaps fortunately, however, May doesn’t simply leave it there. Yet her explanation for why those who run or are employed by the state sometimes act the way they do still seems a little limited, focused as it is on their supposed tendency either to further their own interests or safeguard those of their institutions rather than to remember that they are there to work hard and to serve – something May herself, we are constantly reminded, never omitted to do.

Many would beg to differ on that score. Contrasted with her hyper-venal successor, Boris Johnson, May can seem like a paragon of selfless virtue – until, that is, one remembers some of the lowlights of her own career in high office.

Most obvious of these, of course, is her role in helping to create a ‘hostile environment’ for supposedly illegal immigrants, which led, albeit indirectly, to the Windrush scandal that saw the shameful deportation and harassment of thousands of black Britons – something that carries its inclusion as one of the book’s case studies beyond irony and into the realms of infuriating chutzpah.

Even that, however, cannot compete with May’s attempt to argue in another of her case studies that Parliament’s failure to agree an EU withdrawal agreement along the lines that she had negotiated was mainly down to Labour Party intransigence and, above all, the malign machinations of the then speaker of the House of Commons, John Bercow. Quite why the Labour Party supposedly had a public duty to vote for her deal when May made no serious attempt to create a cross-party consensus that might have helped reconcile millions of Remain voters to the country’s decision to leave the EU is never satisfactorily explained. And how someone whose main concern is systemic failure can have the nerve to suggest that much of the blame for Parliament’s rejection of her deal rests with just one individual is, frankly, beyond me.

The one glaring omission is any sense that the organisation to which May has dedicated her life, the Conservative Party, might be, at least in part, responsible (beyond its Pavlovian support for the police) for some of the scandals on which she focuses, primarily through its chronic underfunding of the country’s core public services, local authorities and key regulatory bodies. May might well be right to argue that the Tories, like other parties, need to think carefully about the kinds of people that it selects as candidates. But unless they move away from their kneejerk ‘private good, public bad’ ideology, nothing much is going to change – the ‘implementation gap’ between good intentions on modern slavery (one of May’s big causes) and its actual prevention being an obvious case in point.

According to the veteran political journalist Andrew Marr, political memoirs serve three purposes: ‘to settle scores, to nudge the dial of the historical verdict, and above all to win a publisher’s advance that is unlikely to be earned out’. May, whatever she might claim, is clearly attempting to do the first and the second of these – in neither case very successfully.

As for the third, who knows? Not that May needs to worry. Her post prime-ministerial appearances on the speechmaking circuit don’t merit a mention. This is presumably because that would undermine the sense of her supposedly selfless commitment to public service she is at such pains to project. However, they have reportedly netted her well over £2 million and counting. Unless you worry that even this won’t be enough to keep her and her husband, Philip, in walking holidays in Switzerland, where, apparently, she first conceived of this book, I honestly wouldn’t waste your time with it.