The Silent Enemy is a black and white 1958 British action film directed by William Fairchild and starring Laurence Harvey, Dawn Addams, Michael Craig and John Clements.

The British are worried that this new tactic will afford the Italians naval supremacy in the Mediterranean and the ability to strike their primary target, the Royal Navy base at Gibraltar.

Meanwhile, from Algeciras in neutral Spain, Italian expert on underwater operations Antonio Tomolino is secretly watching the British base in Gibraltar and planning new attacks.

After a further series of attacks against ships in Gibraltar harbour and an attempt to recover secret documents from a wrecked aircraft, Crabb visits Algeciras to discover the Italians' base of operations.

Crabb ignores orders and, with the manned torpedo repaired, he and another diver infiltrate the docks at Algeciras, launching a preemptive strike on the Olterra that destroys the ship, workshop and crew.

Unfortunately the film fails to present a particularly convincing or authentic picture of Crabb; the main role is played with boyish earnestness and stereotyped heroic style by a bearded Laurence Harvey.

The underwater scenes, beautifully photographed by Egil Woxholt, forcefully recreate the gloomy, claustrophobic atmosphere of the Mediterranean depths.