Decima Flottiglia MAS in Gibraltar

The military history of Gibraltar during World War II exemplifies Gibraltar's position as a British fortress since the early 18th century and as a vital factor in British military strategy, both as a foothold on the continent of Europe, and as a bastion of British sea power. During World War II, Gibraltar served a vital role in both the Atlantic Theatre and the Mediterranean Theatre, controlling virtually all naval traffic into and out of the Mediterranean Sea from the Atlantic Ocean.

In addition to its commanding position, Gibraltar provided a strongly defended harbour from which ships could operate in both the Atlantic and the Mediterranean. Force H, under the command of Vice-Admiral James Somerville was based in Gibraltar and had the task of maintaining naval superiority and providing a strong escort for convoys to and from the besieged island of Malta. During the course of the war, Gibraltar came under aerial bombardment from Vichy French aircraft and from aircraft of the Italian Royal Air Force (Regia Aeronautica) based on Sardinia. Additionally, the fortress was the focus of underwater attacks by the Italian Royal Navy (Regia Marina) commando frogman unit (Decima Flottiglia MAS) and their human torpedoes. This Italian unit was based on the interned Italian ship SS Olterra in the nearby Spanish harbour of Algeciras. A number of attacks were also carried out by Spanish and Gibraltarian agents acting on behalf of the German Abwehr.

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