As the first of two planned cinematic chapters in the optimistic quest to adapt Stephen King’s 1000 page ode to the nervous breakdown, “It” has had an appropriately monstrous marketing campaign. Anyone in London who has descended into the tube recently will have seen the ads depicting the bright, bulbous face of Pennywise the child-eating clown and his red balloon. They suggest that veteran horror director Andres Muschietti, who also steered 2013’s ‘Mama’ to critical acclaim, has crafted a modern, psychological and relentlessly macabre re-imagining of the 1986 horror classic – in keeping with Tim Curry’s twisted performance in the book’s earlier 1990 TV adaptation.

But “It”, it turns out, is ‘hilarious. This is a film that is set-up to be so comically at odds with itself that none of it – none of it – can be taken seriously. Following loosely King’s footsteps, ‘It’ takes us to the serenely bucolic town of Derry, Maine, where behind the Spielbergian facades and heavy-handed period placement (the cinema is showing Batman and Lethal Weapon 2) an insidious darkness supposedly lurks. It is hidden from all apart from the pounding orchestral cues that telegraph sinister events an hour before they happen, the spectacular supernatural phenomena blasting about all over the place and a missing persons count that could deplete a small nation.

As usual in horror films, the grown-ups have better things to do than to wonder why their children haven’t come home in a year, so it is up to a merry crew of precocious and sweary eleven-year-olds to sort this nonsense out. And they have a pretty rough time of it – each regularly becoming the target of Pennywise’s personalised nightmare trips.

Indeed, these pre-teens have a remarkable capacity for experiencing the kind of trauma that would send Alien’s Ellen Ripley to the Priory, only to turn up the next day ready to swap penis sizes. But between these spasms of gratuitous horror lurks a rather sweet, if hardly groundbreaking, coming-of-age story. American kids do what American kids have always done – zigzag bikes dangerously down leafy streets, cheerfully throw them down onto the tarmac when they’re done, and leap into the local quarry from perilous heights because it’s the 1980s and that’s just what people did, according to Hollywood.

However, it must be said that whichever dramatic institute schooled these boys has turned them into astounding young actors. Not only do they spare us the endearing but uncomfortable school play qualities of the earliest Harry Potters, they spat and riff in a way that is supremely natural. And the jokes are actually funny too.

But in the middle of any tender, human moment, when we might have momentarily forgotten about cannibalistic clowns roaming the plumbing, the score will slide an octave and we know that a rampaging headless corpse or suppurating demon will crash into frame any second. It might just be me, but I just can’t take someone being strangled by their own hair that seriously.

But these people should have known what they were in for when they came to Derry in the first place: a small-town small town boasting a tired high street, a slaughterhouse and a sprawling gothic ruin overshadowed by a tree that twists malevolently at its rusty gate, hungry for lynchings. Meanwhile, enormous tetanus-riddled sewer grates dribble their dark contents into mountain creeks. The school bully, not content with being zitty and malicious, is murderously psycopathic. It is a place that exists to facilitate plucking people off street corners and eating them, so it is hardly surprising when this begins to happen.

“It” becomes a kind of festival of gratuity, morphing into whatever genre it feels like whenever it chooses at any given moment. Every so often it will remember its perfunctory credentials and toss in an explosion of horror that is always imaginatively visualised and mad enough to be rewarding, if never actually frightening. But it’s all so rich, colourful and unapologetically drenched in nostalgia that it becomes intoxicating, to the extent that King’s Pennywise character is probably the least interesting thing in it. Perhaps, then, this is a heretical adaptation of King’s novel. But who cares when it’s this much fun.

7/10

‘It’ is directed by Andres Muschietti