2026 marks the 70th anniversary of this suspenseful science-horror classic from legendary writer Jimmy Sangster as X the Unknown makes its worldwide premiere in 4K

2026 marks the 70th anniversary of this suspenseful science-horror classic from legendary writer Jimmy Sangster. Often considered an unofficial part of the Quatermass franchise, the film makes its debut on Blu-ray and 4K UHD – the latest to be restored by the teams at Hammer and Silver Salt Restoration.

When a soldier dies from apparent radiation poisoning, the Atomic Energy Commission sends scientist Dr. Royston (Oscar-winner Dean Jagger) to investigate. Despite extensive testing no source can be found – until a mysterious radioactive, mud-like entity resurfaces and begins claiming more victims. What do you do when the killer can’t be stopped – or even understood?

Special Features

This edition comrpises:

Two discs featuring three iterations of the film: the widescreen 1.66:1 UK Theatrical Version, the fullscreen 1.37:1 As-Filmed Version, and the widescreen 1.85:1 US Theatrical Version.

English, French, Italian, Spanish, German subtitles on all versions of the film.

Brand-new 5.1 mix for 1.37:1, 1.66:1 and 1.85:1 versions, alongside the original mono film soundtrack.

Discover brand new film commentaries, documentaries, and more. The discs include:

Making-of documentary about the production of X the Unknown.

New and archive commentaries with experts that include; Nigel Kneale biographer Andy Murray, film historian David Kalat, writer/producer Dr Steve Haberman.

Displaced and Damned : A documentary following the career of Joseph Losey – the original X the Unknown director who departed the project before shooting commenced – and his storied journey through Hollywood to Hammer films, via blacklisting and exile.

An exploration of the groundbreaking work of special effects artist, Les Bowie, including archive audio interviews with fellow special effects technicians and audio from Christopher Lee.

A Man on the Beach : the rarely seen short film featuring Jimmy Sangster’s first scripted work and directed by Joe Losey.

And more.

Technical Features

Language Mono / 5.1 / English

Number of discs 2 x UHD Blu-ray

Region UHD region Free

Certification PG

Run time Feature: 1 Hour and 20 Minutes

Subtitles English, French, Italian, Spanish, German

Actors Dean Jagger, Edward chapman, Leo Mckern

Directed By Leslie Norman

Written By Jimmy Sangster

Produced By Anthony Hinds

Release Date 1956

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