n recent years, “keeping the receipts” has come to refer to a somewhat paranoid diligence, whereby someone mentally stores the evidence of another’s behaviour, should they ever need it in future. The phrase has particular bite in the context of social media and smartphones, which produce constant digital records that can be filed away for future reference. A society in which people hold “receipts” on one another can scarcely be a happy one, and will eventually enter a vicious circle of suspicion, once it becomes clear that everyone is maintaining dossiers on everybody else. But when dealing with known liars and frauds, it would be remiss not to keep some kind of paper trail. Peter Oborne is a consummate receipt-keeper. His efforts to hold political elites to account go well beyond those of regular reporting, and have snowballed over the last 20 years into a one-man moral crusade against lying in public life. He tackled the issue head-on in his 2005 book The Rise of Political Lying, the same year that he presented a Channel 4 documentary Why Politicians Can’t Tell the Truth. He reveals in his new book that “by the time the Blair premiership ended in 2007, I had got into the habit of keeping a file of political lies”. The figure who has come to dominate that file during the past five years is our current prime minister. The Assault on Truth may sound like another book about “post-truth”, “fake news” or the threat posed by French philosophers. But make no mistake: this is a book about Boris Johnson. Oborne is clinical and merciless in his account of Johnson’s mendacity, building up his case item by item, footnote by footnote. The forensic nature of the task leads him to adopt an entire new citation system, such that the bottom third of a page is often made up of URLs, dates and textual references. The book it most reminded me of was Christopher Hitchens’s The Trial of Henry Kissinger. In a sane world it would be a political obituary. Oborne is precise, sober and occasionally repetitive. He rehearses the plain facts of Johnson’s lies, over the course of his journalistic and political careers. Some of these are well-known, such as those that led him to be sacked from the Times aged 23 (fabricating a quote) and later the shadow cabinet (falsely denying that he’d had an affair with a Spectator colleague). He also details the serial lies told about Jeremy Corbyn, Labour and the impending Brexit deal over the course of the 2019 election campaign, a time when Oborne maintained a purpose-built website to keep track of all the falsehoods. “I have been a political reporter for almost three decades,” he writes, “I have never encountered a senior British politician who lies and fabricates so regularly, so shamelessly and so systematically as Boris Johnson.” What makes Oborne’s dossier so gripping is that he and Johnson share the same cultural and professional milieu, or at least they did. Johnson hired Oborne as political correspondent for the Spectator, and Oborne is occasionally overcome with praise for his moral nemesis. He describes Johnson as “by some margin the most brilliant political journalist of his generation, with a talent that at times crossed over the line to genius”, and as “a joy to work for, a fine editor and a loyal colleague with the quickest mind I’ve ever encountered”. Yet he blames Johnson personally for a dramatic deterioration in the credibility of public life and the legitimacy of institutions. Britain has entered a “nightmare epistemological universe”, and the key moment in this transition was 24 July 2019, the day that Johnson entered 10 Downing Street. Oborne thus elevates Johnson to a Dionysian status in British politics, trampling gleefully over everything that Tories have held dear for over 200 years, leaving a wreckage in his wake. He accuses Vote Leave (especially Dominic Cummings) and its financial backers of launching a “reverse takeover” of the Conservative party, preying on the fact that the party’s membership and innate respect for tradition had long been falling. Cummings et al “despised the Conservative party and hated British institutions”. For Johnson, they offered him a path to power, and that was enough. Oborne’s moral compass is that of traditional, pre-Thatcherite conservatism: Edmund Burke, Michael Oakeshott and the rules that emerged over time to govern the conduct of parliament and civil service. For a Tory such as Oborne, the public record is, or should be, the final word. His faith in Victorian norms of bureaucracy and parliament sometimes borders on the quaint, but is clearly authentic. For an example of where his more dull and worthy brand of conservatism survives, he turns repeatedly to Angela Merkel. It’s not just the contemporary Conservative party that appals Oborne, but developments in his own profession. Newspapers, their owners and their staff have colluded with politicians to smear and fabricate without fear. Oborne’s efforts to expose these practices have not been without personal cost. Finding no mainstream media outlet that was willing to publish him on the topic of journalistic malpractice around Johnson, he took his evidence to openDemocracy, who published his article “British journalists have become part of Johnson’s fake news machine” in October 2019. Sombrely he reports that, since the piece appeared, “the mainstream British press and media is to all intents and purposes barred to me”. Johnson, Vote Leave and Rupert Murdoch are roundly condemned. Donald Trump, despite featuring in the subtitle of the book, performs more of a cameo role, serving as the comparator to Johnson and partner in epistemological crime. But the underlying conditions of these phenomena get off too lightly, perhaps because – as a Brexit-voting Tory – Oborne is unwilling to fully confront the role of the market and of nationalism in the dethroning of the liberal ethic of public service. It is impressive, moving even, to witness Corbyn being defended so staunchly by someone who no doubt disagrees with everything he stands for. But Oborne cannot help but blame the left for an underlying malaise, of which Johnson is the most aggressive symptom. From Rousseau through to Tony Blair, Oborne sees the left as making greater use of mendacity than the right, as the former is more confident of its ultimate moral goals. If the end justifies the means, then the means can include lying. This, Oborne argues, is what gradually corroded the compact of conservative institutionalism, creating the space for showmen such as Johnson to exploit the vacuum. Johnson and Trump “combine rightwing political instincts with progressive methods”. The dogma of Thatcherism goes unmentioned. It is a relief, in many ways, that social media features so little in a book on political lies. There is something determinedly analogue about Oborne’s mission, and the faith he places in official documentation such as Hansard. And yet it becomes hard to explain the rise of Johnson’s (or Trump’s) brand of free-wheeling political entertainment without at some point addressing changes in the technologies and funding of our media. Johnson’s lies are no secret, though they have rarely been as well documented as they are in The Assault on Truth. The question is why they – and books such as this – do him so little harm. In a world of peer-to-peer surveillance, where our honesty and character are constantly being tracked by managers, credit-raters, customers and one another, there is a certain relief in the spectacle of the outrageous leader who seems immune to this collection of “receipts”. In the meantime, Oborne offers a stirring rage against the dying of the establishment light. • William Davies is author of This Is Not Normal: The Collapse of Liberal Britain (Verso). The Assault on Truth: Boris Johnson, Donald Trump and the Emergence of a New Moral Barbarism is published by Simon & Schuster (£12.99) To buy a copy go to guardianbookshop.com. Delivery charges may apply.