ARI Aster’s horror arrives trailing the kind of hype usually reserved for a meteorite heading for Earth. On contact, however, the result is more Blair Witch underwhelming than mind-alteringly terrifying.

There is no denying that Aster, who caused a stir with his previous horror, Hereditary, has an eye for an arresting visual and that there are some scenes here that will linger long in the mind. But the scariest thing since sliced bread with a fortnight’s mould on it, a genre-shattering original? Only if you don’t get out to the cinema, or anywhere else much, or have managed to get through life without seeing folk horror classic The Wicker Man.

Midsommar begins in America, with psychology student Dani (Florence Pugh) in crisis. She has never needed the support of her boyfriend more but Christian (Jack Reynor) is tiring of the drama that seems to come with Dani. Encouraged by his friends, he is on the verge of breaking up with her.

But they stumble on, with Dani tagging along with Christian and his millennial friends when they head to Sweden, home to one of their number, to take in his community’s Midsommar festival.

Aster works hard to induce unease in the audience, beginning with a long driving shot calling to mind The Shining. Everything is about to go topsy-turvy, and that is before someone brings out the mushrooms, and the long sunny days and short nights start to mess with the tourists' minds.

On first sight of the commune and its endlessly smiling, flute-playing residents, most folk would turn tail back to Stockholm if only from the fear of being bored to death.

Yet we have to believe that our intrepid travellers would stick around. So whether from curiosity, a desire to seem open minded and not be impolite, or simply the amount of hallucinogenics they are imbibing, the American outsiders, joined by a couple from London, go with the flow of the commune.

Dani, the film’s central character, is by far the most intriguing, arriving in Sweden weakened and vulnerable, and growing stronger by the day. The more time goes by, the more clearly she sees Christian’s failings. While one could see this as feminist and empowering in a bleakly comic way, the film is also not above pandering to cliches about fertility and what drives women.

From the initial set up it is a long haul to an impressive finish. Strong stomachs will be tested and nerves frayed. Mostly, it was patience that took the hardest pounding as the inevitable ending finally sailed into view. Memorable, certainly. Enjoyable? Hardly.