You can’t buy a box of Mackintosh’s Weekend chocolates any more. On eBay, however, there is a fridge magnet showing all the multicoloured sweets it once contained. When invited by a new boyfriend to celebrate the 1979 New Year with his chums at a house party in Kent, Hannah Strode, a young left-leaning journalist, buys a box of Weekend for her host. “Ah”, says the loftily amused Gideon as he takes the offering, “the kids will love these”.

Agonisingly for Hannah, the gaudy box is produced at dinner that very night, clearly incongruous among all the sparkling chandeliers and cut-glass decanters. “Good God” mutters the man next to her “What are these?” What should she have brought, you wonder. Would Bendicks Bittermints have cut the mustard?

How imperceptible and easily transgressed are the subtle barriers in English society, and if you get them wrong, how painful the punishments. And how accurately Anthony Quinn skewers them.

In London, Burning, the latest novel in his fine series about the capital, Hannah shares centre stage with three other characters: Freddie, a “self-made man in love with his creator”, whom she profiles in her newspaper, probably more forgivingly than he deserves; Callum, a gentle English lecturer from Newry, condemned by accent, name and prejudice as coming from the wrong side in the Troubles, whose defence she undertakes; and Vicky, a formidably brave young police officer, shockingly patronised and objectified by colleagues and villains alike, who helps them all and who will, without doubt, continue to fight for justice long after we have closed this book.

Because of a series of accidents the lives of these four become, like a skein of discarded Christmas lights, inextricably entangled. Quinn is aware of the risks of such a technique. His epigraph quotes John Buchan: “Coincidence . . . stretches out a hundred long arms hourly across the earth”, and Callum treats his students (and us) to a tremendous lecture on the subject. But Quinn needn’t have worried. He prepares the ground so well that we are rather delighted than surprised by the developing connections between them all. As the plot gathers pace, their co-operation becomes increasingly, and pleasingly essential.

As always, he gets the period details bang to rights. In the comfortable shires, people drink stingers and old fashioneds while elsewhere they all down prodigious quantities of lager; virtually everybody smokes. Vicky, becoming increasingly and dangerously involved in a drive to root out police corruption, calls her boss from a stinky phone-box whose receiver has “the faint, moist warmth of recent use”; in those innocent pre-Tinder days, Hannah tries out the personal ads in a newspaper, while Callum is lulled to sleep by the phlegmatic, soporific voice of John Peel on the radio, very late at night.

But this is the Winter of Discontent, when the extreme right National Front is on the march; when there is graffiti that reads “Enoch was right” and “Keep Britain white”; when strikes lead to rubbish being piled up on pavements and bodies remaining unburned and unburied. Margaret Thatcher, with her promise to defeat the unions, is about to be voted in, and the activities of the IRA are approaching a dangerous crescendo, horrifyingly reached with the murder of Airey Neave.

In the novel he is named Anthony Middleton, a war-hero of considerable charm and impressive insouciance who suffers an identical fate, even down to the make of the car in which he is killed. It is a shattering moment. A subsequent apparently copycat murder, however, raises even larger questions, tantalising and intriguing the reader right up to the last page.

Then, as now, the atmosphere of the country has become deeply and dangerously polarised. Even lovely, wise, even-handed Hannah finds herself briefly wondering if she is being too tribal when she questions whether there could actually be such a thing as a sexy Tory. It is, she decides, a moot point.

Yet, despite the irresistible and sombre contemporary echoes, this is not primarily a polemical or even depressing book. Peopled by the kind of strong, fully realised individuals whom you could easily identify in a crowd, it is skilfully plotted and written with a rare elegance, sinuous wit and even optimism. It is a deeply satisfactory read.

London, Burning, by Anthony Quinn, Little, Brown, RRP£14.99, 341 pages

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