on the side of Germany. In May 2013 files were released showing MI6 spent the present-day equivalent of more than $200 million bribing senior Spanish military officers, ship owners and other agents to keep Spain out of the war. Resources and trade Despite lacking cash, oil and other supplies, Francoist Spain was able to supply some essential materials to Germany. There was a series of secret war-time trade agreements between the two countries. The principal resource was wolfram (or tungsten) ore from German-owned mines in Galicia, northwestern Spain. Tungsten was essential to Germany for its advanced precision engineering and therefore for armament production. Despite Allied attempts to buy all available supplies, which rocketed in price, and diplomatic efforts to influence Spain, supplies to Germany continued until August 1944. Payment for wolfram was effectively set against the Spanish debt to Germany. Other minerals included iron ore, zinc, lead and mercury. Spain also acted as a conduit for goods from South America, for example, industrial diamonds and platinum. After the war, evidence was found of significant gold transactions between Germany and Spain, ceasing only in May 1945. It was believed that these were derived from Nazi looting of occupied lands, but attempts by the Allies to obtain control of the gold and return it were largely frustrated. Espionage and sabotage As long as Spain permitted it, the Abwehr – the German intelligence organisation – was able to operate in Spain and Spanish Morocco, often with cooperation of the Nationalist government. Gibraltar's installations were a prime target for sabotage, using sympathetic anti-British Spanish workers. One such attack occurred in June 1943, when a bomb caused a fire and explosions in the dockyard. The British were generally more successful after this and managed to use turned agents and sympathetic anti-Fascist Spaniards to uncover subsequent attacks. A total of 43 sabotage attempts were prevented in this way. By January 1944, a Gibraltarian and two Spanish workers, convicted of attempted sabotage, had been executed. The Abwehr also financed, trained and equipped saboteurs to attack British naval assets. The Germans contacted a Spanish staff officer from Campo de Gibraltar, Lieutenant Colonel Eleuterio Sánchez Rubio, a Spanish army officer, member of Falange and coordinator of the intelligence operations in the Campo, to establish a network of saboteurs with access to Gibraltar. Sánchez Rubio designated Emilio Plazas Tejera, also a member of Falange, as operations chief of the organisation.