Almeida theatre, London, N1, until 29 November

I have to admit that it was probably unfair to reread The Line of Beauty before seeing the Almeida’s new adaptation, written by Jack Holden and directed by Michael Grandage. Alan Hollinghurst’s 2004 Booker prize-winner is a Jamesian masterpiece constructed as a string of set-pieces at social occasions, like pearls on a necklace which ultimately snaps. The main attraction is his uncannily penetrating eye for the subtle mechanics of human interaction. Without that authorial X-ray vision, is it just one party after another?

Hollinghurst’s premise was pilfered for Emerald Fennell’s vacuous Saltburn but unlike that film it features recognisable human beings. Bookended by the two Tory election victories of 1983 and 1987, it finds middle-class climber Nick Guest (Jasper Talbot) lodging at the Kensington home of glibly ambitious Tory MP Gerald Fedden (Charles Edwards) and banking heiress Rachel (Claudia Harrison). Nick is university friend to Toby (Leo Suter) and informal carer to the brittle, dangerous Cat (Ellie Bamber). He has one foot in this bubble of money and power, another in the more democratic gay scene, and his head in a study of style in Henry James, who “wrote about money, and the effects it has on people”. He has to learn – slowly, painfully – not to mistake beauty for value.

Holden efficiently compresses the novel’s vast social whirl into a dozen actors, although the downsizing takes some getting used to. Hollinghurst’s pantheon of moneyed ghouls is distilled into a single Thatcherite demon, Derek “Badger” Brogan, a task that Robert Portal pulls off with monstrous red-faced gusto. Set designer Christopher Oram deftly evokes various opulent venues simply by changing the furniture, including a cocaine-dusted toilet cistern and a floating neon ogee – the elongated S-shape that Hogarth called “the line of beauty”.

Another impressive visual effect is the unveiling of Suter’s Thor-like physique during a poolside scene. But the fact that Toby’s improbable anatomy, and its discombobulating impact on Nick, are played for laughs gives away the play’s shortage of erotic heat despite the efforts of Alistair Nwachukwu and Arty Froushan as Nick’s financially polarised lovers Leo and Wani. The humour is broader than the novel’s and the laughs a little cheaper. Holden also presses down harder on the thematic buttons. A drinking game in which a shot must be taken every time someone says the word “beauty” would get the Almeida shut down.

Tweaking the timeframe creates some problems, too. Now it somehow takes Nick and Wani four years to produce a single issue of their style magazine, which is a very long time in publishing, even allowing for sex, cocaine and holidays. The historical precision of Oram’s costumes doesn’t extend to the music choices. I accept that most people won’t give a hoot that the Communards’ Don’t Leave Me This Way plays a crucial role in a scene set three years before it was recorded but it’s a sloppy and avoidable anachronism in a story where the shifting styles and mores of the 1980s matter a great deal. Details, as Henry James knew, are far from trivial.

It's Talbot who keeps the drama persuasive. Playing Nick is a tall order. He needs to be gauche yet compelling, awkward yet bold. We have to find his determination to live for the pursuit of beauty somehow admirable as well as foolish, and his slow moral corrosion forgivable. The character gave Dan Stevens his breakthrough role in Andrew Davies’s 2006 BBC adaptation and Talbot, who anchors every scene right through to his dazzlingly sad final monologue, deserves a similar boost.

Hollinghurst’s backloaded plot pays off explosively after the interval. If the first half is a likeable social comedy about class and pretence, then the second has unstoppable tragic momentum. In the novel, Cat complains that “landslide” has become a cliche to describe a thumping election win when it really means a sudden gravitational catastrophe. Well, here’s the landslide – a cascade of deaths and expulsions; double lives exposed and debts collected; all these stubborn realities that Nick finds unbearably unbeautiful.

One devastating force is the onslaught of Aids and visceral homophobia. Another is the revenge of privilege on an indelible interloper, as the older Feddens, Edwards and Harrison, are finally unleashed in a magnificent triptych of showdowns observed from the wings by the rest of the cast. When Gerald screams at Nick “who are you?”, it’s a very good question. Nick has been living in a castle made of glass. While it's enjoyable enough to watch it glitter, The Line of Beauty only finds its theatrical urgency when the walls begin to crack and shatter.

Dorian Lynskey is an author and podcaster and the Nerve’s theatre critic