John le Carré – David Cornwell as he then was – grew up among the lies of his fraudster father Ronnie. He then entered a world of secrets, reporting on leftist students when he was at Oxford before working in intelligence for MI5 and MI6. Deception was his domain and as much as he hated Ronnie he worried about coming from the same “mad genes-bank”. Instead he became a novelist; a less damaging way to tell lies. Le Carré felt intruded on by Adam Sisman’s 2015 biography and quickly offered an “antidote” in his memoir The Pigeon Tunnel. The letters bring further exposure but they’ve been sensitively edited by his son Tim, who died suddenly in June, with the emphasis thrown on his father’s best self and industrious literary career: the days spent writing in longhand at his desk (his wife typed up the pages), the exhaustive research he carried out (both before embarking on a novel and after he’d done the penultimate draft), the firm control he exerted over blurbs, jacket designs and layout. He changed publishers and dumped editors but always with courtesy. “There’s no sillier fellow than the writer complaining about critics,” he said, but on at least one occasion he did so, protesting to the editor of the Observer about Clive James’s “sloppy” debunking of his work. Le Carré thought childhood a writer’s greatest resource, and the letters throw light on the Cornwell years. The shame caused by his father’s “incurable criminality” was compounded by his mother’s abandonment of him when he was five; he didn’t see her again till he was 22 and his later letters to her, though solicitous, are far from warm – “[I] find her awfully hard to tolerate”. After an abrupt departure from boarding school he went to Germany and later spent five terms as a German teacher at Eton (“I don’t think I’ve ever met so much arrogance”). He made a “silly” early marriage to Ann, whom he nicknamed “A-mouse” and eventually left (“I’m a pig, I know I am”), before marrying Jane, whom he nicknamed “Cow” and who was indispensable as both his editor and gatekeeper. For a time he worked as an illustrator and his drawings and caricatures enrich the letters. Film and television producers were keen to adapt his novels from the start, and he was buoyed by the success of the adaptations, as his letters to Alec Guinness demonstrate. Other actors he wrote to, often with excruciatingly fulsome admiration, include Ralph Fiennes and Stephen Fry. The letters to his mentor and Smiley prototype Vivian Green are more revealing, as are his scornful asides on Kim Philby. With fellow authors, including Tom Stoppard, he’s friskier. To Philip Roth he jokes that he’s useless at giving writerly advice – “I was no use to Joyce on Ulysses, fucked up completely when Kafka needed me, all I could suggest to Nabokov was ‘couldn’t you just maybe give her a couple more years’.” The high literary references are unusual: he was more of a Wodehouse man and read with painful slowness, in part because of dyslexia. “My love life has always been a disaster area,” he told his brother Tony, and worried, needlessly, how much the Sisman biography would expose. There’s no naming names here, either, but the letters to Susan Anderson (a museum curator) and Yvette Pierpaoli (an aid worker) read like those of a lover, and to Susan Kennaway, his affair with whom is well known, he describes himself as “a mole too used to the dark to believe in light”. More might have come of his romancing had not so many of his letters been destroyed. Tim Cornwell lists a few of the losses and there may have been diplomatic omissions. Le Carré himself was diligent in keeping letters he received from fans and oddballs – and in replying to them. Le Carré’s later years were blighted by a disaffection with what Britain had become. He marched against war in Iraq and described Tony Blair as “a mendacious little show-off … fucking up the world in his Noddy car”. Boris Johnson was as bad or worse (“Cowardice & bullying go hand-in-hand, & Johnson is a practitioner of both”), and further afield there was Trump (“a thin-skinned, truthless, vengeful, pitiless ego-maniac”) and Putin (“appointing himself Ruler for Life”). As for Brexit – “An act of economic suicide mounted by charlatans” – it so dismayed him that he applied for (and got) an Irish passport; his grandmother, who’d looked after him as a boy, came from Cork. Despite his friendships with literary, theatrical and political grandees, he took pains to “stay outside the citadel” and refused a CBE when offered one by Margaret Thatcher, whom he found surprisingly “admirable”. He continued turning down British honours, as well as an appearance on Desert Island Discs (“I have great admiration for your programme and it seems to get along fine without me”), while accepting awards in France and Germany. The older he got, the more embattled he became: against pharmaceutical companies, warmongers and even spies. “In my day, we were told we were little apostles for truth, pledged to speak fearlessly to power,” he said. Now spies were “craven”, allowing the world to be led by “a handful of jingoistic adventurers and imperialist fantasists, backed by a lot of dark money and manipulation: populism led from above”. The lasting impression the letters leave is of his doubleness: “A right little cutthroat on my way up, I’ve also been an insecure softie.” He’s acidic one moment, warm-hearted the next, sometimes about the same person – Ian McEwan, for instance, whose novel Amsterdam he dismisses as “piss awful” but to whom he writes with affection and respect after they’ve met. He feels the same sense of division about himself, describing his first two novels as “unputdownable. I prefer them to Dickens” yet worrying if his work is up to scratch. “I’ve had an amazing run,” he says when facing death, and exults in his life with Jane as two “old honeymooners on a cliff”. But the residue of unhappiness can’t be denied: “Looks so terribly impressive from the outside. But the inside has been such a ferment of buried anger and lovelessness from childhood that it was sometimes almost uncontainable.” What contained it was the fiction. And the letters show how hard he worked to get the fiction right. A Private Spy, The Letters of John le Carré 1945-2020, edited by Tim Cornwell, is published by Viking (£30). To support the Guardian and Observer order your copy at guardianbookshop.com. Delivery charges may apply.