“Even before France had fallen, Hitler’s generals lobbied the German leader for permission to roll on into Spain and wrest control of Gibraltar from the British.”

SHORTLY AFTER THE defeat of France in 1940, Adolf Hitler directed his generals to begin preparations for Nazi Germany’s next bold plan — the seizure of Gibraltar.

Few in Berlin doubted the ultimate success of the operation, codenamed Felix. After nearly a year of uninterrupted military triumphs, it seemed a safe bet that the swastika would soon be flying over Britain’s enclave in southern Spain. Of course, events unfolded very differently.

Fortress Gibraltar

Located on the north shore of the eight-mile strait that separates Europe from Africa, the 2.6-square mile Gibraltar peninsula is dominated by a 1,300-foot tall mountain known simply as “the Rock.” Britain has controlled the vital outpost that commands the narrow waterway linking the Atlantic to the Mediterranean since the 1701 to 1714 War of Spanish Succession.

Home to a Royal Navy fleet as well a sizeable RAF presence, the Gibraltar station represented a key link in a chain of bases that connected the United Kingdom to its vast Empire in the east. When war broke out in 1939, the tiny territory became a strongpoint from which the Allies could challenge any Nazi moves into the Western Med and even the South Atlantic.

Even before France’s capitulation, Hitler’s generals lobbied the German leader for permission to roll on into Spain and wrest control of Gibraltar from the British. In fact, the Third Reich’s most senior military commander, Reichsmarshal Hermann Goering, had been pressing the Fuhrer all summer to shelve plans to invade the U.K., known as Operation Sea Lion, and grab Gibraltar as a prelude to a thrust into North Africa. With the crucial straits closed to Allied shipping, the Luftwaffe chief argued, access to the Suez, the Middle East, and even India would be effectively cut off, driving yet another nail into Britain’s coffin. By summer’s end, the Fuhrer was convinced. And while plans would proceed against the British Isles, Operation Felix would go ahead as well.

Order of Battle

The conquest of the Rock was to be led by one of Germany’s leading mountain warfare commanders, general Ludwig Kübler. His force included the elite Großdeutschland Regiment along with elements of the German 1^st Mountain Division. Three engineer battalions and a detachment of commandos from the Brandenburg Regiment would also take part in the attack. The entire corps was to be supported by 26 battalions of artillery as well as two dive-bomber wings with fighter escorts. The invasion force would cross the Pyrenees into Spain and drive southwest to Gibraltar. To the north, a smaller formation consisting of one motorized infantry division and two panzer divisions would protect the main body’s right flank. All units would converge on the final objective, after which the small British colony would be bombed and shelled into submission.

The military campaign was to be preceded by a diplomatic offensive aimed at securing Spanish support.

Franco’s Cold Feet

Despite repeated efforts by Berlin to bring fascist Spain into the war on the side of the Axis, Francisco Franco remained aloof. Inwardly, the Spanish dictator recoiled at the prospect of joining the conflict. Still reeling from a civil war that had devastated the local economy, Madrid had no interest in military conquest. Furthermore, the notorious generalissimo worried that by even allowing the Nazis safe passage through Spain to strike at Gibraltar, he would be throwing open the door to Allied bombing or even a full-on retaliatory invasion later in the war. Talks between Nazi officials and Franco’s lieutenants sputtered on all autumn and into 1941. By February, it became evident to Hitler that the Spanish had no intention of ever declaring war on Britain, or even allowing a Nazi invasion force onto the Iberian Peninsula. But by that point, Hitler’s priorities had shifted to the east as the might of Germany’s military gathered for the epic invasion of the Soviet Union. Gibraltar would simply have to wait. 

Back to the Drawing Board

Despite the delays, the German high command kept the capture of Gibraltar on the table. In fact, a revision of the plan, dubbed Operation Felix-Heinrich, was ordered in the spring of 1941. It called for units to be detached from the Eastern Front and sent to Spain once the Red Army had been annihilated. Berlin was confident that the invasion would kick off sometime in October – with or without Franco’s blessing. Yet as the conquest of the Soviet Union bogged down, the Gibraltar gambit was once again put on hold as no units could be spared. The plan would continue to be revised and tweaked right up to 1944, but as the fortunes of war turned against the Nazis, the opportunity to seize the Rock never again presented itself.

British Reaction

The prospect of a German campaign aimed at snatching Gibraltar hardly came as a surprise to London. From the war’s outset, British military planners fully expected the hammer to fall on the vital outpost.

By the summer of 1940, Vichy French and Italian warplanes were striking the outpost regularly. In preparation for bolder enemy action, the British added new runways to the facility, deployed anti-aircraft batteries and reinforced the colony with four infantry battalions and an artillery regiment. The neck of Gibraltar’s peninsula bristled with bunkers and gun emplacements while a series of dense minefields made the land approaches virtually impenetrable. Most impressively, an army of British and Canadian engineers transformed the mountain itself into a labyrinth of tunnels, bunkers, and storerooms as well as barracks capable of housing 16,000 troops. More than 25 kms (18 miles) of new passageways were excavated in preparation of an enemy invasion – a significant expansion of the 11 kms (7 miles) of shafts that had been gradually carved out of the mountain since the 18^th century. Fortunately for the Allies, these defences would never be tested.

Operation Tracer

The British even had a top secret backup plan should the colony ever fall to the Nazis. Operation Tracer, a scheme concocted in 1941 by Royal Naval intelligence, called for a squad of three observers, two surgeons and a senior officer to be left behind within the maze of tunnels inside the Rock of Gibraltar following an enemy occupation. In the event the post was about to be overrun, engineers would seal the operatives into a chamber hidden in the upper recesses of the mountain complex. Once entombed within the 45 x 16-foot (66 square meter) space, the agents could monitor the base and port below via a series of observation slits cut into the walls.

Positioned next to the dugout was a massive storage tank that could hold up to 45,000 litres of water as well as a supply room where more than a year’s worth of rations could be stockpiled. The living space was equipped with plumbing and even toilets. A bicycle-powered electrical generator could charge batteries that would run lights and a radio transmitter.

The stay-behind team was expected to hole up in the cork-padded, sound-proof room, monitor the base and broadcast intelligence reports of troop and ship movements until supplies gave out or the Allies mounted a counter assault.

Although details of the plan were kept under wraps even after the war, rumours persisted for decades about secret rooms hidden somewhere within the mountain’s network of tunnels. In 1997, a group of local spelunkers finally stumbled across the long-fabled chamber. Since then, researchers have uncovered details about Operation Tracer and the plan’s volunteers.

(Originally published on Oct. 31, 2013)