HIV/Aids has been the subject of numerous great plays and films, from the explosive theatre of Larry Kramer and Tony Kushner and experimental cinema of Derek Jarman and Gus van Sant to the crowd-pleasing warmth and activism of Pride and 120 BPM. British television has often lagged behind, its depictions generally restricted to adaptations, plot devices on serials or more rounded portrayals in soap opera (notably with Mark Fowler’s death in EastEnders).

The US has been more ready to explore the subject in-depth, with Ryan Murphy’s Pose the most recent example, but such portrayals have rarely featured on the main TV networks.

While plays and films can sneak out independently, television has, until recently, required the benediction of a traditional broadcaster whose conservatism is as much economic as cultural. Why would viewers tune in, week after week, for a story of such unremitting tragedy? Where is the light and shade?

Olly Alexander as Ritchie, one of a group of teenagers living under the shadow of Aids in 1980s London

“It’s a tricky sell,” admits Russell T Davies, whose five-part Channel 4 drama It’s a Sin (named after Pet Shop Boys' defiant 1987 chart-topper) offers irrefutable and unexpectedly joyful answers to those questions. “I wrote it to be exhilarating — it can’t just be sad moments, because that wouldn’t be true. Life doesn’t stop when terrible things happen. To miss those boys, you need to see how vital they were.”

Those “boys” are three teenagers who find themselves and each other under the shadow of Aids in 1980s London. Closeted, effervescent Ritchie (Olly Alexander) yearns to escape the tedium of the Isle of Wight; brittle, flamboyant Roscoe (Omari Douglas) is on the run, outed by his evangelical Nigerian parents; sensible, sheltered Welsh valleys boy Colin (Callum Scott Howells) is an apprentice at a Savile Row tailors. Together with their confidante Jill (Lydia West), they transform their tumbledown bedsit into “The Pink Palace”.

“A lot of gay dramas had focused on people in their thirties or forties,” says Davies, who turned 18 in 1981. “I wanted to talk about the young people who died and were forgotten more quickly, before they could make a mark. It sat on various desks at various channels for a while.”

Davies had to resolve the curious paradox that his story might be too gloomy, but also not gloomy enough. “I was told it would be commissioned if it started in the middle of the crisis then flashed back: starting when they’re young and having fun, with Aids just a rumour on the horizon, could be seen as not very dramatic. I said no, and I’m glad I stuck to my guns.”

Davies built his career on groundbreaking television. In 1994 he introduced an HIV-positive teenager into teatime serial Children’s Ward and, after overseeing Doctor Who’s astonishing regeneration, has delivered on his promise to make only “gay scripts”. Following Banana/Cucumber and A Very English Scandal, among others, It’s a Sin is the apotheosis of a journey Davies began, at least publicly, with Queer as Folk at the tail-end of the ’90s. Amid its taboo-busting gay sex and celebration of Manchester’s queer community, it controversially omitted any mention of HIV/Aids — a decision Davies stands by, having refused to let the lives of gay men be defined by the virus.

The cast of the groundbreaking 1999 show ‘Queer As Folk’, from left to right: Charlie Hunnam, Aidan Gillen and Craig Kelly

The impact of Queer as Folk was felt both in the UK and across the Atlantic. As a result, Neil Patrick Harris jumped at playing a supporting role in It’s A Sin as Colin’s mentor, and was joined by fellow small-screen veterans Stephen Fry (as a closeted, hypocritical Conservative MP), Tracy-Ann Oberman (Ritchie’s supportive acting agent) and Keeley Hawes (Ritchie’s emotionally repressed mother). It also enticed Alexander away from pop stardom in his band Years & Years, resuming an acting career that had been on hold for five years.

“When I was 14, we’d sneak into my friend Caz’s bedroom and watch the episodes in secret,” says Alexander. “These bums, men kissing each other . . . it was very powerful for me, although I didn’t understand why I felt that way at the time. Russell’s work has helped shape my identity as a gay person.”

It has been a long time coming for Davies, who based every story on either first- or second-hand experience. “We shouldn’t spend all our lives looking backwards,” he says. “But every so often you have to stop and make some sort of memorial. So many people died of Aids and their parents said it was cancer. It’s still said to this day. Those false memories can become fixed and untruths pass into history, so it feels like time to say: this is what really happened.”

A Gay Pride march in Trafalgar Square in the late 1970s

The series also reflects a degree of atonement on the part of its creator. “I went on marches but wasn’t on the frontline — I got my head down and worked. But then I felt guilty about it: this slow murder was hard to look at. I still remember the normal, everyday fear that a bump or mark was a sarcoma. I wasn’t one of the great activists, but I’m glad I took the long route because I’ve written something from a different perspective.”

That perspective of decades has ensured It’s a Sin isn’t swamped by anger or grief (although there is plenty of both), making its lessons all the more salient now that HIV/Aids is no longer a death sentence.

“None of it is played with foreboding,” agrees Harris. “I hope younger generations will appreciate what has happened and still needs to happen. The conversation is still alive, necessary and in many ways more important than ever, because we’re at a tipping point with the virus. People care more about their house burning down when they smell smoke.”

Neil Patrick Harris (centre) plays Henry Coltrane, mentor to Colin (Callum Scott Howells, right), an apprentice at a Savile Row tailor

“The older actors flocked to the project,” says Davies. “Every one of them rattled off a list of friends [who had died]. Not a day would pass on set without remembering someone, reviving their memory.”

Oberman remembers someone whose bedclothes were burnt in the garden of a friend’s parents after a visit. Hawes and Harris recall a teacher and friend, respectively, whose deaths from Aids were never given a name. “Someone isn’t at work, things aren’t so good, they pass away,” remembers Harris. “It was all very quiet.”

Fry’s memories come in a torrent: like the young men of It’s a Sin, he moved to London in 1981, although his experiences were very different. “I never liked The Scene, the gay pubs and bars and clubs,” he says. “I thought people would take one look at me and think: no thanks. By the late ’80s, I was aware that had probably saved my life. I found myself sitting on the beds of dying friends, going to funerals with distraught parents . . . I read the script through walls of tears. I saw the faces of all these dead friends, the parents, the whole broken promise of it.”

The boys’ confidante Jill (played by Lydia West)

Part commemoration, part celebration, It’s a Sin is also inadvertently timely. The treatment of those infected unavoidably recalls the early months of the Covid-19 pandemic, complete with PPE, isolation wards, frantic disinfection and conspiracy theories over its origins, albeit driven in those days by an absence rather than a surfeit of information. More positively, advances in virology and immunology made during HIV/Aids research unquestionably contributed to the rapid production of Covid vaccines.

By its very existence, It’s a Sin embodies the enormous strides in equality and representation made since the 1980s, but Davies remains cautious. “Our rights are paper thin and it’s insane to think progress is permanent. You have to keep fighting, which is what I’ve done in my dramas — they’re all about the right to be gay.”

‘It’s A Sin’ begins on Channel 4 at 9pm on January 22 and will be available to stream as a boxset on All 4