The 50th anniversary of the landmark Sexual Offences Act 1967, which partially decriminalised gay sex in Britain, as well as the 60th anniversary of the Wolfenden Report, which first recommended that decriminalisation, have been marked in many important ways, including Tate Britain's exhibition, Queer British Art 1861–1967, and the BBC's "Gay Britannia" season. Lives and works of art and cultures that were previously hidden — sometimes in plain sight, sometimes not — have been revealed in their true natures, and celebrated as such, and an alternative history of the nation has been presented, often tortured and tragic, frequently courageous and inspiring.

The retrospective exposure of a clandestine gay Britain is a continuing preoccupation of one of our finest novelists, Alan Hollinghurst, whose return this month with a new novel, six years after his last, could hardly be better timed.

Hollinghurst began his career with a groundbreaking debut, The Swimming-Pool Library. Set in the summer of 1983, it jumps back to the Twenties, Thirties and Forties, contrasting the modern gay scene with the sexual and romantic lives of gay men of earlier generations. In 2004, Hollinghurst won the Booker Prize for his masterful satire of Eighties amorality, The Line of Beauty. In 2011, he published The Stranger's Child, his secret history of gay literary England, spanning the years 1913 to 2008. That novel was a mystery, of sorts, concerning a famous poem and the deliberate concealing of the sexuality of its author, a young man killed in World War I.

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The new novel, The Sparsholt Affair, in a number of ways takes up where that book leaves off, with the same leaps in time and place, from Oxford in 1940, with German bombers overhead, to London in 1974, with the lights going out during the Three-Day Week, right up to the present day. (We can't say for sure, but this may be the first literary novel to include a mention — an evocative one — for the Range Rover Evoque.)

Again, it concerns closeted gay lives of the past — one of the things the title refers to is a public sex scandal of the pre-Wolfenden period — and out gay lives of the present, culminating in a breathtaking description of a night of drugs and dancing in a gay club: a passage that grabs the reader by the sweaty palm and pulls him or her, elated, through the swirling debauch.

Again, it delineates shifting tastes in art and culture and social behaviours, changing attitudes to sex and relationships — especially gay sex and relationships — and to class. Again, it follows characters over decades, their fortunes ebbing and flowing.

Again, as with all Hollinghurst's work, it is utterly involving, uncannily realised, beautifully written and very moving.

'The Sparsholt Affair' by Alan Hollinghurst (Picador) is available now