The long first part of this eagerly awaited novel occupies one dreamy weekend in the late summer of 1913, the last summer of its kind there ever was to be, to adapt a phrase Alan Hollinghurst himself used in his debut, The Swimming Pool Library. Published in 1988 but set in 1983, that book described a period of spectacular sexual abandon just before the catastrophe of Aids cooled and restrained the ardour of promiscuous gay men. The setting of The Stranger’s Child feels immediately familiar, as do the ironies – elegant people partying on the edge of the abyss – but they are never clichéd, because Hollinghurst writes so carefully and subversively, often with one eyebrow raised in sardonic amusement as he satirises the excesses of his mostly high-born protagonists.

The central character around whom all others gather is a young aristocratic poet named Cecil Valance. He is heir to a baronetcy and 30,000 acres, and is visiting the family of his friend from Cambridge, George Sawle. Cecil is beautiful, insouciant, careless, adored, and both George and his younger sister, 16-year-old Daphne, fall in love with him.

At the end of the weekend, Cecil, who has enjoyed illicit sex with George in local woodland and flirted with Daphne, writes a poem, “Two Acres”, named for the Sawle family home in Middlesex, and dedicates it to the swooning young girl who, like the innocent boy in LP Hartley’s The Go-Between or the mischievous girl in Ian McEwan’s Atonement (both novels that Hollinghurst has evidently read carefully and learned from), understands little of the adult world of sex and secrets, and even less of homosexuality.

We then shift abruptly forward in time to 1926. Daphne is now Lady Valance, having married Cecil’s worthless brother, and Cecil himself has been killed during the first world war as you knew he would be. His statue stands in one of the rooms of the family’s neo-gothic mansion.

As with Rupert Brooke, Cecil’s reputation as a poet has been enhanced by early death – just think of what he might have achieved! – and “Two Acres”, like Brooke’s “The Old Vicarage Grantchester”, has become an emblematic poem, evoking a lost prewar world. We are told on several occasions that, at the time of Cecil’s death, lines from “Two Acres” were quoted by Churchill in The Times. It’s the beginning of a literary cult that resonates through the decades as the novel unfolds from 1913 to the present in six distinct parts.

Hollinghurst is interested in what it means to love someone or something that is perpetually unattainable as well as in class, history and how it feels to be an outsider at the top table of high privilege. Reading the first part of the novel one thinks of the pastoral elegies of AE Housman, and in particular of A Shropshire Lad and its subtext of homoerotic longing and conflation of youth and mortality. This strange, haunting collection in which the poet mourns lads already dead or those soon to die was published in 1896, yet it found a renewed popularity with the generation who went to war in 1914, with all those young men destined, like the fictional Cecil, to be lost in the trenches of the western front, and with their bereaved families.

Hollinghurst has always been adept at juxtaposing tenderness and depravity, at combining a highly refined literary sensibility with the instincts of a pornographer. The shock, and aesthetic surprise, of reading him for the first time was to encounter a writer determined to write so explicitly about gay sex in a style that was as extreme as it was deliberative and rarefied.

So frequent and all-consuming was this in The Swimming Pool Library and The Folding Star (1994), and so scarce was the female presence, that as a reader you were left numbed by the relentlessness and the repetition but also beguiled by the artfulness of it all.

The sex in The Stranger’s Child is unusually bashful for Hollinghurst; it occurs in the margins, referenced but not described. There are also complex female characters, notably Daphne whom we see as an almost-child, as a young unhappily married woman and then in old age.

Yet the homoerotic yearning of old remains strong, and gay characters feature throughout. They include a suburban clerk with literary aspirations who later becomes one of the many Cecil biographers attempting to decode “Two Acres”. As the years pass, and those present during that golden, misunderstood weekend in Middlesex die, the poem becomes encrusted in legend. It is the role of the biographer to unravel the truths of Cecil’s short life and of the poem. Its creation-myth was that it had been written for and about Daphne, but in fact it was written for and about her brother, with some hard sex excised from the final draft.

The Stranger’s Child is broader in scope and more generous in outlook than anything Hollinghurst has written before as well as being structurally his most ambitious work and his most restrained sexually. What remains absolutely characteristic is the gracefulness of his sentences as he goes about his business, scrupulously scene-shaping and mood-patterning. (No contemporary writer is more fastidious about adverbs; “experimentally” is a recurring favourite here.)

Hollinghurst is essentially a writer of the long moment and of the extended set-piece: the party, the country house weekend, the dinner party. If he has a weakness it is a tendency to over-describe; to seek to convey each and every subtle shift in mood, tone, inflection and nuance. The overall effect is charming and you admire the artistry but it can also be enervating – sometimes you wish that things were more slipshod, rough and urgent in this fictional world, a little less perfect and sumptuously poised.