Portugal during World War II
Upon the start of World War II in 1939, the Portuguese Government announced on 1 September that the 600-year-old Anglo-Portuguese Alliance remained intact, but that since the British did not seek Portuguese assistance, Portugal was free to remain neutral in the war and would do so. In an aide-mémoire of 5 September 1939, the British Government confirmed the understanding. As Hitler's occupation swept across Europe, neutral Portugal became one of the Continent's last escape routes. Portugal managed to remain neutral throughout the war despite extraordinary pressures from both sides, notably over the strategically located Azores islands and over the wolfram (tungsten) trade.
Portugal–United Kingdom relations
Portugal was an official Allied Power in World War I; Portuguese troops were the first to be gassed by German soldiers, yet they received nothing after the Treaty of Versailles. In World War II, Prime Minister António de Oliveira Salazar was committed to the six-century-old treaty (which had been renewed in 1899). Portugal provided assistance not by declaring war but by helping Spain stay neutral and by assuming a co-belligerent status against Germany by leasing air bases in the Azores to the Allies in 1943. It cut off vital shipments of tungsten to Germany in 1944, after heavy Allied pressure. Lisbon was the base for International Red Cross operations aiding Allied POWs, and a main air transit point between Britain and the U.S.