IT, an adaptation of Stephen King’s chiller, was the surprise hit of 2017, grossing more than £584 million worldwide. A little bit Stand By Me with a touch of junior Breakfast Club, it was funny, charming, and in Pennywise the clown it had a villain who was genuinely terrifying. What else to do, then, but ruin it with a sequel?

Given the glut of follow-ups in cinemas, one might have thought the industry was getting better at the art of the reheat. It: Chapter 2, despite some strong performances (James McAvoy and Bill Hader to the fore), returns to the bad habits of sequels past by taking the small and perfectly formed elements of the original and blowing them up like Pennywise’s red balloons until they go “Pop!”

Chapter 2 opens with the final scene from the first film, when the gang of young friends, the self-dubbed Losers’ Club of bullied kids, swear a blood oath to return to their home town of Derry, Maine, if the child snatching monster they called “It” ever came back. As legend has it, Pennywise resurfaces every 27 years.

Sure enough, we’re transported to the noughties, and the fun fair is in town. After a nasty incident that gives a taste of things to come it is obvious that Pennywise’s sleep of the undead is over. Obvious to Mike, that is, the only one of the original bunch not to have moved away from Derry. He sets about assembling the old crowd, all of whom are deeply disturbed by the summons even though their memories of the past have more holes than a clown’s bucket.

There is fun to be had as we see what became of the titchy heroes and heroine. Bill (James McAvoy), is now a writer; Beverly (Jessica Chastain) is a rich designer trapped in a nightmare marriage; Richie (Bill Hader) is still a loudmouth joker only now, as a stand-up, he gets paid for it; Eddie’s germophobia remains a close run thing to his coulrophobia, and so on.

And what of our old chuckle buddy himself? Pennywise has not aged a day, as is often the deal when you are the embodiment of evil. So the tale begins, with each adult forced to once again confront their worst fears as Pennywise messes with their minds.

Chapter 2 is not without its moments (Chastain returning to her childhood home is a corker). But there is too much reliance on special effects, with results that are downright weird, as when the original young cast, now older, are “digitally de-aged” for new scenes. The story would shame Scooby Doo, the tone wanders from mocking to menacing, and Chastain screams a lot.

All this is nothing compared to the chief faults: NEC (Not Enough Clown) initially, and a runtime that is just shy of three hours and feels every second of it. A rocky horror show indeed.