The Phlebotomist by Ella Road explores the future of genetics. Suppose a simple blood test were able to tell us how long we will live and what disease will kill us. If the tests were compulsory and the results publicly available, a new hierarchy based on life expectancy would emerge. Citizens facing chronic illness or early death would struggle to find jobs and spouses. The scientists who administer the tests would come under pressure to falsify the results. And alpha citizens with high-grade DNA would be murdered, and their blood harvested to create fake genetic identities.

This gruesome, ingenious and all-too-believable scenario is presented through a squeaky-clean romance between two young lovebirds. Bea is a professional blood-sampler who runs a side hustle accepting bribes from ailing clients. She’s a smart, ambitious and complicated soul apparently unconcerned by the gravity of her crimes. Her lawyer boyfriend, Aaron, is a descendant of Tennyson who quotes the easy bits from ‘In Memoriam’. Frankly, he’s unbelievable. Tall, slim and handsome, with swept back hair and unblemished skin, he loves to recall his idyllic childhood spent roaming through sun-kissed valleys and picnicking on fresh salmon beside silvery lakes.

The Bea/Aaron relationship lacks jeopardy. Each is hiding a secret but neither is at risk of being exposed by the other. Instead we get an Instagram version of their five-star lives. They romp playfully on a pocket-sprung Ikea mattress. They relax over malt whisky in their minimalist riverside apartment. They enjoy rambling holidays in the wilds of western Ireland. And they engage in low-level bitching about their families as the date of their wedding looms.

The writer has such a facility with dialogue that her scenes last longer than necessary (good for TV commissions, not ideal for stage work). Only in the play’s final half-hour do the long-hidden deceptions break the surface. At this point the script goes from touchy-feely to shouty-wouty. Bea, now pregnant with Aaron’s child, delivers a screed of defeatist rhetoric about the demise of Homo sapiens and the folly of having babies in a world where the air is toxic. She’s supported by her best mate, Char, just back from a save-the-planet holiday, who seethes with righteous anger about man’s inhumanity to polar bears.

It’s a pity that this propaganda — learned by rote from state-funded scientists — prevents the writer from exploring her characters and from showing us what makes them original and eye-catching. That said, this is an exceptional play that successfully conjures up a convincing modern dystopia. Both the leads, Jade Anouka and Rory Fleck Byrne, look like stars. I’d be amazed if this doesn’t become a TV series.

After Edward opens with an unnamed man in medieval togs landing on the stage with a thump. He stands up and converses with a robed cleric named Canterbury, who prattles away while lighting candles but doesn’t reveal the identity of the mysterious man. Enter an American lady seated on a wheeled lavatory that trundles around the stage like an invalid’s chair. Harvey Milk then ambles on and starts to drawl about his life while Quentin Crisp descends on a wooden swing. What’s going on? After a while, and seemingly by accident, the American female reveals herself to be Gertrude Stein. She recalls meeting her lover, Alice B. Toklas, whose lines are spoken by Quentin Crisp.

This lazy confusion persists until finally we learn the identity of the chap at the centre of the action. He is in fact two people: Edward II and the writer/actor Tom Stuart. This is Stuart’s history of gay activism beginning with Edward II who, he alleges, lost his crown because of homophobia rather than through botched leadership. The script’s chief focus is on the 1980s when Stuart was a confused gay schoolboy but his fetish for his sorrowful childhood compels him to regard the history of gay rights as a tragedy.

Is it, though? Since Stuart was a nipper, gays have moved from the closet to the mainstream, and the legalisation of gay marriage has made them part of the establishment. That’s why he has to go back three decades to find material for his angry play. Rather than examining the current threats to gay freedom from Muslim conservatives, he berates right-wing nutters at the fringes of the Tory party long ago. No mention is made of Mrs Thatcher’s desire to protect gay men’s health in the 1980s by mounting a costly public education programme about Aids. Instead she’s treated as a figure of contempt. The crowd hooted with exultant derision as soon as she entered, and when she was forced out through a trapdoor they jeered like religious freaks at a witch-burning.

This allegedly ‘cosmopolitan’ audience seemed not to realise that to celebrate the destruction of a hounded entity is the seed of fascism.