Robin Hardy, the director, who has died aged 86, was best-known for the 1973 film The Wicker Man, whose portrait of a sinister neopagan cult inspired its own cult following and came to define the subgenre of British “folk horror”.

The film began life when the writer Anthony Shaffer approached distributors British Lion in 1972 with a new project, to be based on David Pinner’s 1967 novel Ritual. With the cooperation of Hardy, Shaffer embellished the basic plot – a policeman investigating an occult murder in a remote village – with hefty doses of sex and sacrifice, transferring the action from Cornwall to the fictional Scottish island of Summerisle.

The Wicker Man’s mesmerising final sequence, in which Edward Woodward’s policeman is trapped inside a burning effigy, also differed from its source material. The scene’s horror was further underscored by the choice of filming location, a bleak clifftop in Burrowhead on Scotland’s Machars peninsula. “Never, ever have I been so frightened as when I was in the wicker man itself”, Woodward later recalled. “The heat was intense and I felt at times that I was really burning.”

It was far from the only difficulty on set. Woodward’s co-star Britt Ekland remembered Galloway, where the bulk of filming was done, as “the bleakest place on Earth”. The climactic sacrifice was supposed to be a spring ritual, so Hardy tasked his crew with gluing leaves and blossom onto wind-blasted branches.

Though Christopher Lee, who played the island’s community leader, regarded the film as his best work, early reaction was mixed. The managing director of British Lion judged it unsaleable and demanded severe cuts to the total running time. It was finally released as the B-feature on a double bill alongside Nicolas Roeg’s Don’t Look Now.

That it did not sink into obscurity was largely down to Robin Hardy’s and Lee’s promotion efforts, which eventually took Hardy to New Orleans to work on a new, director-approved cut. The glossy magazine Cinefantastique dedicated its winter 1977 issue to the end result, describing it as “The Citizen Kane of horror movies”.

The tortured production and distribution process only helped to burnish the film’s cult credentials among its more dedicated fans, dubbed “Wicker-heads” by the British tabloid press. In 2003 thousands of devotees converged on Galloway for a two-day celebration of “punks, pagans, and pyromaniacs”, featuring live rock music and a bonfire of a 25-ft effigy. “It is ironic that a film that was intended to acerbically dissect the power structures and beliefs of cults should have gained a cult following,” observed Dr Benjamin Franks of Glasgow University. Hardy was more prosaic: “We did a great job, really, for Scottish tourism.”

Robin St Clair Rimington Hardy was born in Surrey on October 10 1929. His father died when Robin was still an infant and his mother travelled frequently. He therefore had a peripatetic start to his career, studying art in Paris before breaking into film with various documentaries for the National Film Board of Canada.

Returning to London in the 1960s, he set up the advertising agency Hardy Shaffer Ferguson Avery with Anthony Shaffer. Perhaps the strongest influence on his directing style, however, was the King James Bible, its “terrific language and wonderful imagery” instilling a lifelong fascination with the power of ritual.

The Wicker Man apart, Hardy’s other projects attracted scant commercial interest. The Dublin-set slasher flick The Fantasist (1986) had little merit except as a director’s curio, while The Wicker Tree (2011), a companion piece (but not a direct sequel) to Hardy’s earlier classic based on his own novel Cowboys for Christ, divided critics upon its premiere at the Fantasia film festival in Montreal. Hardy later mounted a defence of the film, contrasting it favourably to a much-derided 2006 remake of The Wicker Man starring Nicholas Cage in the Edward Woodward role.

Robin Hardy is survived by his wife, Victoria, and by eight children, one of whom is the film-maker Justin Hardy.

Robin Hardy, born October 10 1929, died July 1 2016