Sometimes, watching TV in the wee dead hours of the night, you chance across a film you’ve somehow never heard of, and find yourself staggered. Psychomania (1972) – in which Beryl Reid gets turned into a frog – is such a movie, transcendently weird in an everyday manner.

The plot is as follows: Mrs Latham (Reid) is a psychic, entered into an unspecified contract with her Satanic butler, Shadwell (George Sanders, politely pouring sherries), granting her eternal life. Her son, Tom (Nicky Henson, doing a Poundland Malcolm McDowell), is the arrogant young leather-clad leader of The Living Dead biker gang.

After finding his dead father’s spectacles, Tom discovers the secret of eternal life: to kill yourself while truly believing you will come back from the dead. So he does, and, rising again, persuades the rest of his gang to follow suit. The bikers all commit suicide (except Tom’s sappy girlfriend), come back, and plan to wreak havoc in their local supermarket for all eternity.

This, it transpires, is somehow in violation of Mrs Latham’s pact with Shadwell, so he turns her into a frog, then turns Tom and gang into standing-stones. The End.

Psychomania (also known as The Death Wheelers and – fantastically – The Frog) fits within a cycle of nasty early-seventies UK horror; however it’s hard to shake the suspicion that the film is one enormous, straight-faced joke, with no one winking to camera to give the game away. Certainly, The Living Dead are the most pathetic bikers ever put onscreen, to an extent that could only be deliberate. When Henson tops himself, the rest of the gang sit around his open grave (brilliantly, he’s buried sitting upright, astride his motorcycle, as if stuffed) making daisy-chains, one strumming an acoustic guitar and whimpering a lame pseudo-folk lament:

“And the world never knew his name

But the chosen few know of his fame

Come join his company

Ridin’ Freee

He really got it on

He rode that sweet machine just like a bomb…”

(elsewhere, the soundtrack is zen-prog-porn-muzak)

Visually, though, the film can be strangely haunting. Psychomania mostly unfolds in an abandoned afternoon Britain, a place that is all suburban town centres or forgotten patchy fields near motorways, shot in early-autumn daylight that lends the colours a cold amber tinge. The aesthetic is much in keeping with the pubic safety information films of the period that took place beside electricity substations or along deserted canal paths; following his suicide, Henson’s body, in fact, is discovered by two tiny children playing alone beside a river.

The most unforgettable sequence – the suicide montage, after the resurrected Henson persuades the rest of the gang to kill themselves (“Oh man! What are we waiting for!?!”)  – has this quality to it. A guy pulls up on his bike beside a drab little tower block, chats with a passing girl, walks inside and then jumps from a high window; another leaps from a busy motorway flyover; another, wrapped in enormous iron chains and wearing only his pants, stumbles along a riverside pathway, then throws himself in. Constantly, in the background, oblivious civilians peddle bicycles, buses pass, nearby cars hum to and fro, a non-fictional background imbuing the thing with a kind of buzzy, hard surrealistic quality.

Psychomania was directed by an Australian, Don Sharp, who had worked on episodes of the eternal The Avengers and directed a lot of Christopher Lee movies. Its main writer was Arnaud d’Usseau, who had written quick crime films in the early 1940s, but then seemingly dropped off the world for three decades, before returning from wherever he had been with this script. (In fact, a victim of the Hollywood blacklist, d’Usseau spent those lost decades working in Europe, writing under various pseudonyms.)

Filmed in Shepperton, near JG Ballard’s house, Psychomania was among the last films the great George Sanders made; he killed himself in Barcelona soon after, but didn’t bother coming back himself. Sanders’s towering presence wraps around the film, ignoring it. It’s almost unbelievable that someone actually had the balls to ask him to appear; but then, watching Psychomania unfold is to constantly, dimly face this exact, unanswerable question: What the hell did they think they were doing?

Written 1995