We open on an ordinary suburban street. A teenage boy is gazing out of a window. A woman – his mother? – is screaming. A man – his father? – is standing in the garden gazing unfocused at whatever lies beyond. The camera draws back to reveal a scene so shocking it hardly computes. Then we flashback to 10 days earlier to begin to understand how they, and the other figures in the scene, got here.

So, with characteristic bravura, begins Russell T Davies’s new drama, Tip Toe. The man in the garden is Clive (David Morrissey), an electrician with two sons – 16-year-old college student George (Jackson Connor) and 25-year-old Saul (Joseph Evans), who helps him in the business when there is enough work to go around – and enduring an unhappy marriage to Marie (Pooky Quesnel).

Ten days before, we find him reluctantly helping out his neighbour Leo (Alan Cumming), an out-and-proud gay man who owns the Spit & Polish bar in Manchester’s Canal Street (the setting, of course, for the masterwork that announced RTD’s arrival on the television scene in 1999, Queer as Folk). Leo has been locked, trouserless, out of his house as he chased a one-night-stand, who had stolen his laptop, down the street. Seventeen kinds of objection to the whole thing can virtually be smelt rising off Clive as he lets Leo into his house to call his friend and keyholder Stephanie (Elizabeth Berrington) to come and rescue him.

After this compelling opening, the rest of the first of Tip Toe’s five hour-long instalments feels more like a flurry of box-ticking than drama. All of human headlines are here. Stephanie, a care worker, arrives delivering a diatribe about a refugee who is clearly older than he looks and leers at girls in the home, but whom she is required to put at the top of the fostering queue (“He’s self-ID, which you lot invented”). Leo goes to work and is admonished for being annoyed by pronouns by one of his transgender staff, Zee (Iz Hesketh), who turns out to be being threatened by her Polish housemates. So Leo, his manager Judy (Luyanda Unati Lewis-Nyawo) and the rest of the staff go round to gather Zee’s stuff. Leo is shocked by the size of Zee’s room. “They all live like this, the kids,” says Judy. “This is what we did to them.” In short order thereafter we have a drag queen at the Spit & Polish absenting himself from the floor when a student (“He knows where I live”) from the school where he teaches turns up; Leo’s friend Melba (Paul Rhys) heckling a comedian about being a Tory, and then delivering a monologue to Leo about the state of gay rights and homophobia today (“It’s back … it’s a storm, a tide, a great tsunami”) and the internet’s power to spread malevolence (Melba reminds him that Tripadvisor reviews claim Leo is a “paedo and a groomer … They say you pay chemically castrated children!”, though in the middle he oddly exempts women, “who are furious and with good reason” from his wrath). Trump’s presidency is folded in (“he has given these men permission to attack us”) and much, much more.

Then there is Clive, whose request for work from Leo while treating him with contempt stands for heterosexual hypocrisy of all kinds (underlined by the fact that he doesn’t know Saul is running an OnlyFans account aimed at women but happily welcoming any paying subscriber, that George is gay and terrified of coming out to his parents, and that – according to Stephanie – he has been unfaithful to Marie. Later, he will also be revealed to be a workplace bully AND a leave voter).

It doesn’t matter where you stand on any of these issues – to tip such untransmuted writing into the mouths of your characters makes it agitprop, not art. It’s exhausting and unengaging for the viewer.

Fortunately, Davies is too good and instinctive a storyteller to keep it up for too long. By the second episode, he has cleared his throat sufficiently to start building a narrative and his characters and let them illustrate the issues about which he is clearly passionate rather than the other way round. It still lacks the discipline that made his other state of the historical/future nation pieces, Years and Years or It’s a Sin, so powerful and moving, but the strands begin to interweave, momentum builds and if the extremity of the conclusion still doesn’t quite ring true, everyone has worked hard to get it as close to authentic and emotionally credible as possible. Cumming keeps the spiky, idiosyncratic Leo just the right side of likable and relatable and Morrissey does his usual magnificent lot by showing just a little.

It’s three and a half stars, rounded up because of all the good and great stuff gone before.

Tip Toe is on Channel 4