Lighthouses have frequently played their part in horror, fantasy and thriller films, from Michael Powell’s The Phantom Light (1935) to Roy Boulting’s Thunder Rock (1942), from Lawrence Huntington’s Tower of Terror (1942) to Robert Eggers’ The Lighthouse (2019). In 1972, Jim O’Connolly took a gaggle of familiar faces off to the Tower of Evil, retitled in the States to include its fictional setting, Horror on Snape Island, which has to rate as one of the silliest but most entertaining of them all. Apart from a few establishing shots, O’Connolly and his cohorts never ventured from Shepperton Studios, the budget not stretching to real, and potentially hazardous, location shooting – Snape Island, it’s eponymous lighthouse, the network of caves beneath it and the sea voyage needed to get there were all created in soundstages on the banks of the Queen Mary Reservoir rather than off some indeterminate coastline.

O’Connolly’s screenplay (based on a story written by George Baxt) takes an odd route through its tale of mad brothers, Phoenician temples, drug-addled hippies and gory murders. We start with the arrival on Snape of two fishermen, father and son John (George Coulouris) and Hamp Gurney (Jack Watson). They find a severed hand and are soon up to their ankles in dead bodies, finding several mutilated bodies before John is stabbed to death by a naked, shrieking and clearly deeply traumatised young woman, Penny (Candace Glendenning), who leaps out of a closet. Taken back to the mainland, Penny is placed in the care of Dr Simpson (Anthony Valentine), an odd sort of psychiatrist who uses psychedelic, coloured lights to hypnotise her and she reveals how her friends – Des (Robin Askwith), Gary (John Hamill) and Mae (Seretta Wilson), all sporting not-very-convincing American accents – were slaughtered by an unseen assailant. Later, philanthropist Lawrence Bakewell (Dennis Price) finances an expedition to Snape Island for a team of inappropriately attired experts – archaeologists Dan (Derek Fowlds) and Nora Winthrop (Anna Palk), Phoenician art expert Rose Mason (Jill Haworth) and her former fiancé Adam Masters (Mark Edwards) with American detective Evan Brent (Bryant Haliday) along for the ride to prove Penny’s innocence – to search for the Phoenician artefacts he believes are hidden there (Des was found impaled on a golden spear). Inevitably, more murders occur until the killer is revealed to be Hamp’s insane brother Saul (Frederic Abbott), a hulking, hirsute brute akin to “The Man” from Death Line (1972) and the equally murderous brother in The Beast in the Cellar (1971).

It’s all completely nuts, full of grisly murders, terrible accents and the kind of sex-and-drug obsessed young people that only ever existed in the mind of a middle-aged man (by the time he shot Tower of Evil, O’Connolly was a positively archaic 45 years old and probably genuinely believed that hip young things were prone to utterances like “this place is really far out”) and yet because of all that and its many other eccentricities, it’s a hugely enjoyable film. Much of the fun stems from the terrific cast, chock full of faces and bodies already very familiar or about to become so, many of them lined up simply to meet nasty ends. The phoniness of the sets and the unconvincing establishing shot of the model lighthouse seem appropriate to the absurdity of the proceedings though the sets give the film an almost surreal atmosphere, the swirling fog eerily punctured by Kenneth V. Jones’ marvellously discordant score to startling effect.

O’Connolly knew the audience he and his producer, the indefatigable Richard Gordon, were aiming for, packing Tower of Evil with lashings of gore and plentiful nudity. We never get to see the “orgiastic ritual” that Nora tells us was part and parcel of worshipping the Phoenician god Baal, more’s the pity, but his game cast have a tendency to shed clothing, much of it eye-wateringly of its time and not at all suitable for a trip to the remote, foggy site of a recent massacre, with commendable gusto.

It all comes to a very effective climax in production designer Disley Jones’ budget-defying underground temple (quite what a temple to a god worshipped by the ancient Phoenician peoples of the eastern Mediterranean is doing under a lighthouse presumably off the coast of Britain is anyone’s guess) where Saul’s identity is revealed, as is the decomposing corpse of his beloved wife Martha and more people die before the tower is blown sky high and the sun begins to comes up.

It’s an early run through of many of the themes that would resurface in earnest during the slasher boom initiated by the success of John Carpenter’s Halloween (1978), with inventive killings and a tendency to “punish” anyone who has sex (as this is 1972 and stars mainly young people, that’s almost everyone) with instant and grisly death. It doesn’t have two brain cells in its metaphorical head (which makes its pairing with Hammer’s more cerebral Demons of the Mind (1972) all the more baffling) but as it bumbles around the oddly structured plot, throwing as much flesh and blood at the audience as censors of the day would allow (in the States, a sex scene between Nora and Hamp’s oafish nephew Brom (Gary Hamilton) was cut, while in the UK it was Saul’s fiery death that got trimmed) it’s hard not to be charmed by it. In Italy, it was sold as a giallo, under the title Perché il dio Fenecio continua as uccidere? (that’s Why Does the Phoenician God Keep Killing? in English) while the Germans tried to lure in any nascent zombie film fans there might have been about by misleadingly retitling it Der Turm der Lebenden Leichen/Tower of the Living Corpses.

Under any title, Tower of Evil is rollicking good fun – as silly as it gets, with a plot that really doesn’t bear scrutiny and some occasionally very shaky acting, but that’s all just part of its allure. No-one in their right mind could claim it to be a great film, but it is a hugely entertaining one, and sometimes that’s all you need. Savour the ludicrous dialogue, wallow comfortably in its sleaze (it’s far tackier than many of its contemporaries and all the better for it) and soak up that unreal atmosphere and it’s as good a way as any of passing 89 minutes of your time.