The Rock of Gibraltar was a stage on which one of World War II's most absorbing intelligence battle of wits was played out.
The history of the Defence Security Office (DSO) in Gibraltar, released by the Security Service and published by The National Archives in March 2005, was documented in fascinating detail in 1945 by the head of the DSO's Security Intelligence Department, David Scherr.
David Scherr, who went on to receive an OBE for his work, was a young Spanish-speaking Intelligence Corps officer serving in Gibraltar in 1942 when the Security Service's representative there decided he needed an assistant to run his agent operations across the border into Spain.
Both the German and the Spanish Intelligence Services regarded the Rock's military and naval facilities as an important strategic target against which to plan sabotage attacks.
For the next two years, Scherr was to be at the centre of a web of espionage and sabotage worthy of a spy novel. The stakes were high. If Scherr and his staff failed, Gibraltar would be vulnerable to enemy sabotage and its vital contribution to Britain's war effort could be seriously reduced.
Spain was nominally neutral during World War II, though under General Franco's far-right Nationalist regime it was politically aligned with Nazi Germany. Spain did not actually join the Axis side but it collaborated with the Nazis in many areas. The Spanish intelligence service had a close working relationship with its German opposite number, the Abwehr.
The two countries had common interests in Gibraltar. Spain had long claimed ownership of the territory, which had been held by Britain since 1703, and Germany wanted to break Britain's control of the vital Straits of Gibraltar to secure naval access to the Mediterranean. It was clear that Gibraltar's naval dockyard and airfield would be high-priority targets in the event of war.
The Abwehr had bases on both sides of the Straits, in Tangier and elsewhere in Spanish-ruled Morocco as well as in Algeciras on the opposite side of the Bay of Gibraltar. The Germans were thus able to monitor Allied shipping movements into and out of the Mediterranean. There was also a large Abwehr station in Madrid, which supervised sabotage operations against the Rock undertaken locally from the Algeciras office.
The Spanish intelligence service also had a strong presence along the coast between Gibraltar and Algeciras, where it had a regional HQ.
The Spanish and German intelligence services often actively collaborated against Britain. Both had recruited local (mostly Spanish) agents, many of whom were fanatically anti-British. One of the few factors in the DSO's favour was the support that it received from a number of anti-Franco Spaniards. They had opposed Franco's Nationalists during the Civil War of the 1930s, had survived the post-war purges, and were now fervently anti-Nazi.
The Double Cross System
The Nazis and their Spanish allies initially seemed to have the advantage in the secret war for Gibraltar. However, the British were able to use the "Double Cross" technique - that of identifying enemy agents and "turning" them into double agents for the British authorities - just as effectively in Gibraltar as they did in Britain.
DSO staff identified many hostile agents and either arrested them or turned them into double cross agents. No successful act of land-based sabotage occurred after July 1943, once the "screen" erected by the DSO's double agent network was in place. A total of 43 sabotage attacks on the naval base were forestalled through the use of double cross agents. Sea-borne attacks remained a problem; a number, including several carried out by Italian frogmen, were successful.
One case in Scherr's history illustrates the exceptional skills and bravery of the agents involved. An agent known as NAG was, in Scherr's estimation, by far the most enterprising and courageous of all the Gibraltar double cross agents. NAG, a Basque, was employed in the dockyard as a lorry driver.
In May 1943 a German agent approached NAG in an attempt to recruit him. NAG was asked to undertake a sabotage attack on a British minelayer, HMS Manxman, which had been used as a fast resupply vessel to carry supplies to the garrison on Malta. NAG's task was to place an explosive device on the ship, or if access to it proved impossible, to conceal it in the armaments store on shore or among the oil storage tanks nearby. NAG reported the approach to the DSO and was run by Scherr as a double agent for the rest of the war.
Over the following year, NAG was repeatedly given sabotage materials, including high explosive bombs, to use against the British naval base. He either handed these over to Scherr or in some cases destroyed them himself. He also helped to frustrate sabotage attacks by other German agents, whose activities he uncovered through clever intelligence work.
Mainly as a result of NAG's efforts, all the Germans' subsequent attempts to set up sabotage networks failed. All of this was done without arousing German suspicions that he was collaborating with the British.
Furthermore, NAG provided a remarkably complete picture of German sabotage operations against Gibraltar. His reports enabled the British Government to make a detailed protest to the Spanish Government in late January 1944. As The Times reported (2 February 1944), "the evidence was produced in the clearest form and speedy remedies were requested."
By this time, Franco's attitude to Nazi Germany had begun to change as the tide of war turned decisively against Hitler. On 3 February 1944, the Spanish government issued a statement of "strict neutrality" in which it promised "the fulfilment of duties appertaining to such strict neutrality, both from Spanish nationals and from foreign subjects." The German intelligence operation in southern Spain was shut down as a result.
NAG's successes were achieved at great personal risk while he and his family continued to live in Spain. He was awarded the King's Medal for Courage in the Cause of Freedom in September 1945.
In his account, Scherr also describes his first encounter with another of his Gibraltar agents:
"Just as the interview I was having with another member of the public was drawing inconclusively to an end, I was called into the next room to cope with a most extraordinary visitor. This was a woman in her 30s whose dress, mannerisms, speech and general appearance made her a rather seedy but not unattractive imitation of the seductive female spy of the thrillerette type.
She sat down in front of the office desk, crossed her legs, adjusting the hem of her dress to reveal them to the best advantage, slowly lit a cigarette, inhaling and breathing out the smoke in the approved furtive, reticent fashion, looking down her long and aquiline nose at the same time, and then smiled across at her interrogator-to-be and said, in cosmopolitan English, "I am the Queen of Hearts. Who are you?"
Married to a Spanish naval officer who was the harbour master in one of the small ports of the Bay of Gibraltar, the Queen of Hearts was able to provide valuable information about a particularly clever and successful series of underwater attacks on Allied shipping off Gibraltar.
Before the DSO had fully established its double cross agent network in Gibraltar, the Rock's military installations suffered several serious attacks. These were carried out by Spanish agents recruited by the German intelligence service, the Abwehr. Two such agents were Luis Lopez Córdon Cuenca and José Martin Munoz.
Cuenca was captured in Gibraltar in 1943 and charged with "acting with intent to assist the enemy, and with having in his possession a bomb intended to cause an explosion in the dockyard." During his trial in August 1943, he claimed that he did not know that the package that delivered to a house in Gibraltar contained a German-made bomb. He also referred to threats allegedly made against his family.
The prosecutor described how Cuenca had dealings in La Linea, just across the border, with a Spanish man named Blas Castro who had spoken of blowing up an ammunition tunnel in the dockyard. According to a witness, Cuenca described how explosives could be brought into Gibraltar. When the witness suggested hiding them in lemons, oranges or cabbages, Cuenca answered: "No, it is easiest in bananas." He was convicted on 31 August 1943 and was sentenced to death.
Munoz, a 19-year-old worker from La Linea, was arrested in July 1943. He was accused of having caused a suspicious fire in the Gibraltar dockyard on 30 June 1943. Witnesses described how "sheets of flame shot into the air and a thick cloud of black smoke swirled back over the top of the Rock," in the words of The Times' report (1 July 1943). He was also charged with having hidden a bomb in the coal-hole of a local café. At his trial in October 1943, he pleaded guilty to the first charge and the second charge was withdrawn. He was sentenced to death for having acted with "intent to assist the enemy by an act designed to impede naval operations or to endanger life."
Both men were hanged on 11 January 1944 by the veteran British hangman Albert Pierrepoint, who travelled undercover to Gibraltar to carry out the executions.
More information on the Cuenca and Munoz cases can be found on file KV 2/2114 at The National Archives.