This was the Allied overall designation for the establishment of bases in the Azores island group, part of Portugal in the Atlantic (October 1943 onward).
Comprising nine islands some 500 miles (800 km) off Portugal in the Atlantic Ocean, the archipelago was to have become the seat of the Portuguese government in the event that Axis forces overran the Iberian peninsula. This was deemed not to be unlikely during 1941, and in May of that year President Franklin D. Roosevelt ordered the preparation of a 25,000-man US force to retake the islands should they fall into German hands and become air and naval bases for the further prosecution of the German war on Allied convoys in the Atlantic.
The Allies also wanted the use of the islands as bases from which to enhance the protection of their convoys and, after lengthy negotiations with the Portuguese government, the British received permission to use air bases in the Azores, resulting initially in ‘Alacrity’. This permission was denied to the Americans, and it was only in 1944, therefore, that US aircraft (with British markings) were permitted to operate from the Azores to help complete the closure of the ‘black hole’ in the central Atlantic, which could not be covered by land-based aircraft from either side of the ocean and for that reason had been much favoured by U-boat wolfpacks.