“Her brain has become overloaded by what it has seen... or done.”

Tower Of Evil (or Terror On Snape Island) doesn't have the most auspicious of starts, as we are treated to a shot of an obvious model lighthouse swathed in dry ice. But things get better very quickly. We then see two fishermen approaching the island in a boat called the Sea Ghost. What are they up to? We ask. Dunno - but dirty deeds seem afoot.

Once there they find a severed human hand, and a naked bloke lying face down in a pool of blood. The signs are not looking good, but neither discovery seems to shock them much. Did they know something was wrong on the island, or are they just poor actors?

Inside the tower, they find a naked woman, also dead, and accidentally knock her already-severed head down the stairs. In a nearby shed there's poor old Robin Askwith, impaled to the wall with a big spear. And in a cupboard there's a mad naked girl, who wastes no time stabbing the older of the two fishermen to death, before her kill-crazy rampage is brought to an end in the time-honoured British horror movie tradition of being twatted with a big stick.

What can we gather from this little prelude? Well, the special effects - particularly the headless body and the severed hand - are very realistic. It has also been very gory, there has been copious full-frontal nudity, and it appears that Robin Askwith has been put out of his misery quite early in the proceedings.

Cut to doctor Anthony Valentine, who reckons that the mad girl Penelope (Candace Glendinning) has been driven out of her mind: "Her brain has become overloaded by what it has seen... or done."

Penelope is one of a group of American tourists who were visiting the country for a jazz festival (what is it about film makers and jazz festivals? I am sure that any actual teenager in the early 70s wouldn't have been seen dead anywhere near one), and utilising the power of disco lighting, the doctor manages to bring on a flashback.

The four "kids" turn up on the island, and ignoring one of the girl's reservations: "I get feelings of evil from this island..." decide to smoke some grass and enjoy themselves, Askwith (in a terrible American accent) calming her nerves by telling her: "That's just me wanting to ball ya."

Just when the flashback is getting interesting, we cut back to the present. And Derek "Heartbeat" Fowlds, who reckons the spear which offed Askwith is Phoenician, and wants to mount an expedition to the island to find out if it's the home of an ancient burial ground. He assembles a crack team of four sex addicts who all appear to have slept with each other, and they head off to the island with the younger fisherman from the beginning of the film (who goes by the name of Hamp), a long haired chap in a pair of very tight jeans, and a load of cases of dynamite (of course). 

Hamp finds a photo of his brother and his wife - the couple lived on the island until recently (aha!), and, as he tells the group: "Snape Island never brought anything but misery to anyone..." (aha!)

Meanwhile, back in the hospital, Penelope's disco treatment carries on - bringing on more flashbacks. The entire group get naked and Askwith is the first to get it - pinned to the wall by a cackling loon. Next is a girl called May in her bed, then Penelope's boyfriend - who loses his hand before getting chopped to pieces. Over, and over, and over again to the soundtrack of Penelope screaming. Who is the madman? Could it be Hamp's bother, Saul? Could it be someone else we haven't been told about yet? Is it Penrod, the mild-mannered janitor? If you're still awake, I won't spoil the ending.

Back in the present the boat explodes, people have sex and a rotting cadaver turns up in the rocking chair. Nearly everyone dies (quite gorily), there's more explosions and a strange twist at the end.

Tower Of Evil is a bizarre one, and no mistake. It's very American in its "lots of people have already died, I think I'll wander off on my own" approach, yet very British in many ways. It zaps backwards and forwards rather than just running in a straight line, and has high production values. But it is just not camp enough to be funny, and not serious enough to be frightening.