Of all modern writers Swift is the most likely to act on Kingsley Amis’s advice to his son: write a sentence like “He finished his drink, and left.” Early in Here We Are, set in Brighton in 1959, he introduces us to Eddie Costello, a showbiz reporter, who occasionally slips into the saloon bar of the Walpole “for a pint of Bass and a shufty”. This is a world of Woodbines, racing tips and a sniff of the barmaid’s apron. It’s a long way from Hensher’s realm of jabbering, precocious adolescents.

My word, how they talk! A Small Revolution in Germany is really an intellectual rework display in Sheffield, the city where Hensher grew up, and Oxford, where he went after school. The exchanges between Spike, the narrator, and his five pals read like a sixth-form companion piece for the Four Yorkshiremen sketch: Five Pretentious Yorkshire Boys and a Girl, perhaps.

“I’ve been reading Ibsen.”
“Ibsen’s no good. It’s Marx you want.” “Yesterday’s man. Try Bakunin.”
“Oh, I adore Bakunin!”

At 16, Spike tells us, “I was obsessed with the poetry of the Sitwells and of Mallarmé.” As was the teenage Hensher, a polymath-in-waiting, the George Steiner of Nether Edge. He writes very well about paintings and music, and generously about other writers, but his own novels do not always catch fire as readers may hope. A Small Revolution is thoroughly entertaining. But the characters’ development is improbable, and the rendering of their adult lives implausible. Are we really meant to accept that three of the gang who discussed Descartes (but not Sheffield Wednesday) in Le Café Carole, planning to disrupt meetings and scrawl obscenities on public buildings, will end up as the home secretary, an ermine-clad QC and a prominent polemical journalist? Three from the same class at a comprehensive school?

Time is the theme on which Hensher arranges his variations: youth against maturity; hope against compromise; betrayal against Larkin’s “unbeatable slow machine”. The “classical Marxists” and “anarcho-syndicalists” of adolescence often become respectable citizens, with public positions to prove it.

The evidence is all around. Yet there is something unconvincing about Hensher’s treatment of these idealists made wise, or at least better informed, by events. It beggars belief that a young Sheffield lad, setting off for freshers’ week at Oxford, would discard his youthful garb on the train south and put on the green tweed suit that became his adult costume.

The book’s middle section, set on both sides of the Berlin Wall in 1987, works best, even if Spike makes an appalling speech (in length and tone) to an East German on another rail journey. “ is is very much not a piña colada sort of holiday that I and my friend Ogden are undertaking.” People simply don’t talk like that to strangers.

There is also a rape of one friend by another that stretches credulity beyond breaking point. It is amusing, however, to see Christopher Clark, the current Professor of History at Cambridge and then a research student in Berlin, swell a comic scene or two in the role of Australian truth-teller.

In the final pages Hensher invites us to understand that Tracy, later Alexandra, may not have died from a drug overdose but was bumped off by a man she has known all her days. So this contrapuntal novel closes on a discordant note a keener ear would have discerned. Just as it might have spotted that Spike, the only member of the gang never to amend his earnest political views, is the most frightful bore.

Ronnie Deane and Evie White, the illusionist and assistant in Here We Are, are not bores. As “Pablo” and “Eve” they light up the show at the end of the pier, rising through the ranks during the summer season to top the bill when the curtain comes down in September, with the cheers ringing in their ears. We are illusionists, not magicians, Ronnie tells his partner, and he proves it in the most spectacular manner, on and off the stage.

Is is the world John Osborne mapped out in The Entertainer, of grotty digs, wily agents and vents called “Lord Archibald”. Young Ronnie, brought up in Bethnal Green, learns the illusionist’s art from “Lorenzo” when he is packed off to Oxfordshire on the outbreak of war. Lorenzo can make anything disappear, and in time Ronnie outstrips his tutor in a way that continues to baffle Evie half a century later when, a widow of a year, she reflects on her life with Jack, Ronnie’s pal and rival in love.

All novelists are illusionists. Characters are theirs to create and command. They appear and disappear, like the spiders’ webs and rainbows that Swift describes in this death-haunted novella. Here we are, he is saying, though not for long, and in any case does anybody really know who we are? In this exquisite, deceptive book, Swift proves again that he is a magnificent writer and — not the same thing — a natural novelist. How other tale-tellers, many of high talent, must envy him.