In the autumn of 1944, with Allied armies fighting their way across France and the largest war in human history at its height, Winston Churchill found a moment to dictate an order about monkeys. He wanted to know the headcount of the apes on the Rock of Gibraltar, and he wanted that number raised. The establishment, he instructed, should be twenty-four animals, and it should be reached as soon as possible and held there thereafter. Two years earlier the troop had nearly vanished. By 1942 the wartime population had collapsed to about seven animals, and a folk prophecy two centuries old suddenly looked as though it might be put to the test. The saying went that while the apes remained on the Rock, the British would remain too. Churchill did not have to believe it. He only had to know that other people did. Every visitor to Gibraltar hears the line within an hour of arriving. While the apes stay on the Rock, the saying goes, so do the British. It is repeated by taxi drivers, printed on postcards, and woven into the patter of every Upper Rock tour. What almost nobody hears is that the legend once came perilously close to being tested, and that a head of state intervened in a wildlife population in the middle of a world war to keep the prophecy intact. The animals are not apes at all, despite the nickname that has stuck for centuries. They are Barbary macaques, a tailless monkey native to the forests of Morocco and Algeria, and the Gibraltar troop is the only wild monkey population anywhere in Europe. The confusion over their name is the smallest of the puzzles that surround them. The bigger questions are where they came from, why a folk superstition fastened itself to them, and how that superstition ended up on a Prime Minister's desk. The origin of the legend is genuinely uncertain, and honest storytelling means saying so. Two accounts compete, and neither can be proved beyond doubt. The most repeated version places it during the Great Siege of 1779 to 1783, when combined French and Spanish forces tried for years to wrest the Rock from Britain. A second account reaches further back, to 1704, shortly after an Anglo-Dutch force took Gibraltar from Spain, when a shepherd is said to have guided Spanish soldiers up a hidden goat path on the sheer eastern face. In both tellings the detail is the same: the monkeys, disturbed in the dark, raised such a commotion that the garrison was alerted and the surprise attack failed. Whether either episode happened as described, or whether the tale was stitched together afterwards to explain a superstition that already existed, is impossible to settle now. What is clear is that by the time the saying was famous, the macaques had become a symbol of the Rock itself, and symbols are dangerous things to lose in wartime. > While the apes remain, so too will the British. A line repeated for two centuries, and in 1942 it came within a handful of animals of being disproved. By the early years of the Second World War the troop was in trouble. Disease, the disruption of the war, and the general strain on a fortress under siege conditions had pushed numbers down sharply. By 1942 the population had fallen to roughly seven animals. Gibraltar at that moment was no ordinary garrison. It guarded the entrance to the Mediterranean, it sheltered the convoys, and its airfield had launched the invasion of North Africa. The near disappearance of its famous monkeys carried a weight far beyond zoology. The concern was never really about the survival of a species in the abstract. It was about morale, and about the meaning people had poured into these animals. Churchill understood symbols better than almost any leader of his age, and he understood what the garrison and the British public might read into the apes vanishing from the Rock at the exact moment the war hung in the balance. Whether or not he privately credited the prophecy is beside the point. He grasped its grip on everyone else. The rescue came in stages, and it is worth separating the two dates that often get blurred together. The collapse to about seven animals was the crisis of 1942. The formal order came later. When word reached London that the troop had crashed, instructions went out to bring fresh animals across from North Africa. Among the new arrivals, several accounts record five females imported from Morocco, remembered by name to this day: Daisy, Beatrice, Jane, Kathleen and Madeline. A naval vessel was used to ferry additional macaques over, and the population was slowly rebuilt. Then, on 2 September 1944, Churchill put the matter in writing in a directive that survives in the historical record. The establishment of the apes on Gibraltar, he instructed, should be twenty-four, and every effort should be made to reach that number quickly and to maintain it thereafter. It remains one of the more extraordinary documents of the war: a Prime Minister, in the year of D-Day, setting an exact target headcount for a colony of monkeys on a r