Jimmy Sangster pens another winner. From the early days of Hammer Film Productions’ horror transition, X the Unknown is boilerplate 1950s monster fare. Like all creative endeavors, however, it doesn’t have to be groundbreaking if it’s done well.
X the Unknown tells the story of a mysterious, radiation-consuming blob spreading terror throughout Scotland. During a training exercise, British soldiers discover a source of radiation where there should be none. The ground cracks open in a thunderous roar of canned sound effects and the film is off. The creature doesn’t make an appearance this early in the film. In fact, it hardly makes an appearance at all.
Missile Test is a big fan of films that hold back their monsters for dramatic effect, but it was done in this film because there was no cash. It’s painfully obvious. The effects in the opening scene resemble something I could have made when I was twelve. That’s not an exaggeration. In Jaws, Stephen Spielberg didn’t show the shark as much as he wanted because the damn thing kept breaking down. We viewers only got glimpses here and there. The result was increased tension. In X the Unknown, director Leslie Norman and company had so few resources that it’s straight famine for us viewers all the way until the end. Still, they worked with what they had.
The monster is especially precious when it does show up on screen. My immediate reaction was that this film ripped off The Blob, but that film was released in 1958. X the Unknown predates The Blob by two years. Some of the snarkier things I wrote in my notes for the 
film were, “Flee! The Marmite has become aware!” and “X the Blood Pudding.” It really does look like English cuisine has come to life and is terrorizing the countryside.
But, I digress. There are people in this film doing things that resemble a plot.
The film stars Dean Jagger, a long way from his Oscar winning performance in Twelve O’Clock High, as Dr. Adam Royston, a nuclear physicist. He is the man in charge of investigating the mysterious explosion the soldiers encountered, and it then falls to him to devise a way to battle the creature. He is assisted by Mac McGill (Leo McKern). Together the two run from site to site as the creature’s body count grows. Eventually Royston discovers a possible method to save everyone that, if it were real, would be one of the greatest discoveries in the history of science. But, viewers can let that slide. This is a 1950s monster flick. Shaky science is no problem.
X the Unknown is largely indistinguishable from any number of nuclear menace monster flicks from the era. The only difference is in its choice of creature. What is impressive about this film is how well it works compared to the resources at hand and the large amount of technical flaws, including some scenes where the dialogue was completely overwhelmed by the music. There was no intention from the filmmakers to make a lasting work of art, and it would be unwise to hold them to such a standard. This film was crafted to make some cash for Hammer, and it did that. It’s also a neat relic from a unique time in film history. That’s what gives the film some importance. It’s a fine example of its genre. If someone happens to be into 1950s monster flicks, X the Unknown is a film worth seeking out.