Anyone brought up in a left-wing family gets used to a particular joshing, voyeuristic line of questioning (“I expect you spent your whole childhood on political marches”, “Did you call each other comrade?”). This is not just an everyday nosiness about an unconventional upbringing; at its worst, it can feel like a discomfiting, albeit disguised form of spite. The question is, in other words: what’s it like to have been raised in a family that had the idiocy or courage (take your pick) to believe it might be able to change the world?

So, one can imagine the glimmer in the publisher’s eye when the idea for this book was first mooted: an authentic portrait of a much-diminished species, the British communist, through the eyes of a red-diaper baby who grew up to be a Times columnist; a tale of quaint habits with serious questions at its heart (despite that corny subtitle echoing Gerald Durrell). According to Aaronovitch, Danny Finkelstein, the Tory peer and his colleague at the Times, keeps asking him when the book is going to be out, because “I want to understand why they did it”. There it goes again – that end-of-history smugness, that needling curiosity.

The trouble is that Aaronovitch knows too much and is, in his intelligent, irritable way, too interested in the multiple backstories involved to reduce his tale to one that will satisfy sceptical, bemused Middle England. Any half-decent account of British communism and the people who made it is bound to yield a long, tortuous, multilayered narrative, and this one is no exception, although it’s a story Aaronovitch never feels fully in charge of, in either theme or tone, for reasons that become clearer by the end.

As a result, Party Animals reads more like a series of extended columns on a number of loosely connected topics. No bad thing. There is a great deal of fascinating material along the way. So we are treated, inter alia, to an early set piece on the visit of Yuri Gagarin to England in 1961, one of the few times when communists were “once again, the people of the future . . . [and] briefly touched the golden face of fashion”; a short history of the rise of the Communist Party in Britain; an account of its relationship to Soviet communism; an anthropological look at the life and habits of CP activists; a long, excoriating feature on show trials of the 1950s; an intriguing case history of domestic political surveillance; and some highly entertaining stories about Aaronovitch’s early political and romantic adventures. The book concludes with an explosive final chapter on the author’s childhood which subtly affects our reading of all that has come before.

Children born in communist families often had a much tougher time of it than those of us who grew up on the left of the Labour Party, which has, for good or ill, always been more closely woven into mainstream British culture and conventions. The Communist Party of Great Britain had a “parallel history, a separate culture and argot, its own music, a distinct cosmology”, quite separate from ordinary concerns of ordinary Britons. (The 11-year-old David was upset he could not join the Cub Scouts; nor was he allowed to read the Beano because its publisher, D C Thomson, was non-union.) Life really did seem to be made up of branch meetings, demonstrations, folk music, rent strikes and party jumble sales. Aaronovitch’s patch of communist north London comes across as a genteel though ground-down sort of place (his family had a house but absolutely no money), with its own plumbers, builders, doctors and accountants – although, rather terrifyingly, Rose the dentist eschewed the use of anaesthetic.

Family life was correspondingly intense and deprived. David’s father, Sam, born into poverty in the East End, was a fierce, clever autodidact whose politics were forged by hatred of “fascism . . . hatred of capitalists who squeezed the blood out of [his] father and made Stepney the slum it is”. An early full-timer in the CP, a role in which he makes an unflattering fictional appearance in Doris Lessing’s Golden Notebook, he failed to win promotion in the party but went on to become a highly productive academic and writer. Like many other activists, Sam was rarely at home and the Aaronovitch children spent most of their time with their mother, the tragically overburdened Lavender, who came from a fractured bourgeois background, but who showed unbending loyalty to both her wandering husband and floundering party.

There is something fatally unresolved at the heart of Party Animals, and it turns on the question of political faith, good or bad. Several times Aaronovitch reminds us that CP members were at the forefront of anti-racist and feminist causes as well as the highly effective campaign against the appalling apartheid regime in South Africa. In a passage lambasting the likes of Roger Scruton, he asks: “If it was criminal to have been a believer in communism and an apologist for Russia, then why was it less criminal to have been a believer in colonialism and an apologist for racism?” Why indeed.

On the other hand, he is doggedly unforgiving on what the CPGB did or didn’t know about Stalinist outrages, though Eric Hobsbawm, the most magisterial of its intellectuals, escapes condemnation by virtue of both his experience of Nazi Germany and the rights afforded a world-class scholar charged with weighing up the relative costs of fascism and communism.

Less attractive is a kind of low-level sneering (I wish that wasn’t the apposite word, but it is) at the day-to-day work of the foot soldiers of British communism, with little interpretive charity shown to the context in which they operated, the language that they used, or their dogged commitment to social action. Even I could tell Danny Finkelstein why they “did it”. I could also tell him why so many of their causes and campaigns have changed the world for the better.

How much of Aaronovitch’s choleric anger at the left, his determination to establish the essentially self-deceiving nature of British socialism, is to do with his parents? To his credit, he tries to unpick the complex connections between personal and political emotions in his final chapter: to tell what he suggests might be the “real story”. We learn more of his parents’ relationship (Sam finally left Lavender after many years of infidelity), his mistrusting relationship with his mother, and his deeply unhappy adolescence, a story that includes compelling details of family therapy sessions sparked by his troubled teenage behaviour.

There are, then, two distinct stories pulsing through this book: that of Aaronovitch, and that of British communism, which deserves to be disentangled more clearly from the author’s complex past and psyche. Still, it is hard not to feel sorry for that clever, neglected young man whose communist childhood gave him an enviable and profound seriousness, but whose family life bequeathed him a fury that has too often been trained back – so publicly, so scathingly – on the left. Let’s hope Lord Finkelstein doesn’t take this story as typical of most left-wing families; it certainly isn’t. As Aaronovitch notes, many children from backgrounds similar to his had a much happier childhood; many have even continued to wage battles for justice in far kinder and more integrated ways.

Party Animals: My Family and Other Communists by David Aaronovitch is published by Jonathan Cape (304pp, £17.99)

This review first appeared in the New Statesman Jan 16 2016