Dr Brian Stanley (Peter Cushing) and Dr David West (Edward Judd), along with his new girlfriend Toni Merrill (Carole Gray), travel to an island off the coast of Ireland to look into the case of a dead local man… who has been discovered with no bones in his body.

With the help of local doctor Reginald Landers (Eddie Byrne), they find out that a group of researchers, seeking a cure for cancer in a secluded laboratory on the island, have accidentally created creatures that absorb all the bones from their victims.

As the island becomes infested by these ‘silicates’, the protagonists must try to discover a way to stop these starfish-blob-like creatures, which have hardened, knobbly skin carapaces and a single, central tentacle that they use to inject bone-dissolving enzymes into their victims.

Axes, shotguns, petrol bombs and dynamite have no effect on these slow, slithering critters, but Stanley and West come up with a solution that involves poisoning the silicates with Strontium-90. As the islanders gather together in a building, with the monsters crawling all over it, the heroes wait to see if their plan will actually work…

I like this flick quite a bit!

The silicates make a very distinctive sound (I’m a sucker for creatures that make peculiar noises, such as the ants in THEM!), which imbues the scenes with a certain creepiness and adds tension too, because once you hear the sound you know a silicate is nearby!
Barry Gray, who did the scores for Gerry Anderson productions like STINGRAY, UFO, THUNDERBIRDS, JOURNEY TO THE FAR SIDE OF THE SUN and SPACE: 1999, provided the electronic sound effects.

The silicates are very slow moving, which I actually like, because – as with un-speedy Romero zombies – I think more anxiety is created when the heroes should be able to keep out of reach of the creatures but you just KNOW the critters are still going to sneak up on them somehow.

The silicates have an unusual way of multiplying, which involves each creature splitting into two every six hours or so. This adds a ticking clock element to the plot, as the protagonists need to deal with this threat before the silicates exponentially grow in number until there’s a million of them. A couple of the creatures are shown subdividing, which calls for the production of milky goo and what looks like tinned spaghetti!

Cushing, Judd and the rest of the cast, including Niall MacGinnis, treat their roles seriously, in a plot that is like a Hammer Films-style horror yarn mixed with a 1950s-era scientists-versus-an-experiment-gone-wrong story.

During the finale, with the besieged islanders seemingly doomed to be overwhelmed by the silicates, there’s a moment where Judd and Cushing decide that it’s best for Carole Gray’s character to be given a lethal injection, rather than risk death-by-silicate. Judd doesn’t inject her at the last moment, because the creatures start to die from radiation poisoning, but it was pretty presumptuous of him to decide to kill her without her consent!

Director Terence Fisher made another blob-monsters-on-an-island movie for Planet Film Productions, called NIGHT OF THE BIG HEAT (known as ISLAND OF THE BURNING DAMNED in the US). But ISLAND OF TERROR is the better film, with such fun moments as a silicate dropping onto an islander from a tree and some brief shots of rubbery, boneless victims, plus there’s a little bit of gore, as Edward Judd is forced to chop off Peter Cushing’s hand before a silicate can digest his bones.

To finish, here are a bunch of posters, some of which misleadingly suggest the movie will feature female nudity!