At a “slave auction” at the Oxford Union in 1987 – an “opportunity to buy your favourite union person for the evening” – there was, according to the university newspaper, frenzied bidding for the services of the kilt-wearing 19-year-old Michael Gove. He went for £35. Gove was known at the time as one of the three pre-eminent orators in the small world of the university debating chamber – the others were Nick Robinson, future BBC political editor, and Simon Stevens, until recently chief executive of NHS England. The previous year’s union president, Boris Johnson, failed to show up for the slave auction and was sold in absentia. Johnson’s own rhetorical style differed from the self-conscious rigour of his peers. He had learned, Simon Kuper writes, in debates at Eton, “to defeat opponents whose arguments were better simply by ignoring their arguments”. He offered instead “carefully timed jokes, calculated lowerings of the voice, and ad hominem jibes”. In this manner, he had won the election to union presidency with the help of various self-described “votaries in the Boris cult”, including Gove and future Covid sceptic Toby Young. The Johnson style was – Kuper notes in this short, sharp and often disturbing examination of how our current politics was first played out at Oxford half a lifetime ago – something new. For maybe 30 years at Oxford, Tories had been in defensive retreat. The manner of Johnson’s immediate Conservative predecessors at the union, Theresa Brasier, her husband-to-be Philip May and her best friend (and future deputy prime minister) Damian Green, was notably halting and circumspect. But by 1984, emboldened by the twin forces of Falklands-era Thatcherism and Brideshead Revisited on the telly, archaic Tory voices – carefully laced with ironies by Johnson – were raucous again. (David Cameron, two years below Johnson at school and Oxford, was a different kind of throwback – rich enough and connected enough to feel himself above the “hackery” of student politics.) It helped this new breed, Kuper argues, that at the union, they were often joking among themselves. The Oxford University Labour Club, high on Billy Bragg and miners’ solidarity marches, boycotted the debating chamber (one result, Kuper suggests, was that they “never learned to speak”). The political big beasts on the left in the second half of the 80s, in university terms, were the Miliband brothers, Dave and Ted, and Eddie Balls and Yvette Cooper, organising rent protests at their respective colleges. The young Keir Starmer, who did his undergraduate degree at Leeds, arrived in 1985 and made a stand about supporting the print workers at Wapping. Johnson could raise predictable guffaws in union debates when characterising socialist students as “retreating into their miserable dungareed caucuses”. All of which is to say: if you thought you knew the extent of the stubbornly incestuous Oxford networks that currently sit at the top of our politics, this book will still surprise you. Financial Times columnist Kuper himself arrived at Oxford in 1988, just after Gove and Johnson had left. Kuper, from a north London comprehensive school, mostly inhabited a different social world to the subjects of his book but, like them, he acknowledges, he was trained by his Oxford humanities degree primarily “to write and speak for a living without much knowledge”. He is scathing of those habits of tutorial teaching at the university, which too frequently rewarded bluffing and charm over industry and doubt. Still, this is not, he insists, “a personal revenge on Oxford”. It’s rather “an attempt to write a group portrait of a set of Tory Brexiteers… who took an ancient route through Oxford to power”. As Johnson himself remarked, if you wanted to know how influential the Oxford Union was in British politics, you had only to look at all the photographs of past presidents (and future prime ministers) on its walls. There was, however, one distinct difference between those characters and their 1980s pretenders. As Kuper observes, the politicians of Anthony Eden and Harold Macmillan’s vintage had been shaped not only by Eton and Oxford but also by war. By 2007, Rory Stewart – who had gone from Eton and Oxford to Iraq and Afghanistan – was observing that in the upper echelons of the Tory party: “Churchill had been replaced by Bertie Wooster.” Kuper argues that though the clique around Johnson believed they were born to power, unlike the swashbucklers of empire they admired, they lacked a cause to fight for. His book details how that “cause” was eventually drummed up by three other near contemporaries at Oxford, all of whom fell under the sway of Norman Stone, the polymathic history professor, alcoholic and sometime adviser to Margaret Thatcher. The first of those was a young Scot, Patrick Robertson, introduced to Stone by Gove at a Burns Night dinner, the second was Dan, now Lord, Hannan, and the third was the most intense of undergraduates, Dominic Cummings. It was Stone who personally nurtured Cummings’s public schoolboy anarchy and who persuaded him to head to Russia after his degree to get a feel for the post-cold war world. Robertson, meanwhile, partly inspired by the historian’s abhorrence of the EU, left Oxford after his second year to devote himself to the Bruges Group of Eurosceptics that he set up while at the university. (Robertson, Kuper points out, now lives in St Moritz, where he runs the public relations firm WorldPR, responsible for the post-Brexit “global Britain” campaign. He is also Kazakhstan’s honorary consul to the Bahamas.) Hannan, among Kuper’s key witnesses here, had grown up in Peru, where his family had a poultry farm. After the collapse of communism, he sniffed – along with Stone – a new “enemy of liberty” in European bureaucracy and found an early acolyte in his absurd Oxford contemporary Jacob Rees-Mogg. On graduating, Hannan persuaded some marginal rightwing MPs to pay him a salary as sole employee of the European Research Group; two decades later he was persuading Johnson to head the leave campaign. And so, as Kuper writes, once again “the timeless paradise of Oxford inspired its inhabitants to produce timeless fantasies like Alice in Wonderland, The Hobbit, Narnia, and, incubating from the late 1980s, Brexit”. It goes without saying, reading this history, that the overwhelming influence of a single kind of graduate from a single university (and often a single school, Eton) at the top of British public life has been profoundly damaging. Kuper offers some solutions – making Oxford exclusively a graduate research institute is one – but also hopes that the pandemic and all that has followed from it might finally mark an end to the British weakness for “the amateur ruler, lightly seasoned by Oxford tutorials”. If so, a suitable epitaph might come from Rees-Mogg, who when challenged in October 2021 as to why Tory MPs were not wearing face masks in parliament, answered: “We on this side know each other.” As if that were all that ever counted. Chums: How a Tiny Caste of Oxford Tories Took Over the UK by Simon Kuper is published by Profile (£16.99). To support the Guardian and Observer order your copy at guardianbookshop.com. Delivery charges may apply