Straits are often the starting point of a colonizing venture, and then, in a phase of decline, the last anchorage point to which the colonizer clings. Malacca, Singapore and Hong Kong were key British settlements, as they controlled the flow of traffic and passage along the route linking London to Sydney. Gibraltar is the ultimate illustration of the British logic of controlling nodal points. Snatched from Spain in 1704 and elevated to the status of Crown colony in 1830, the Rock was an indispensable milestone on the route to India, resurrected by the construction of the Suez Canal, and, in times of crisis, a stronghold for blocking the entrance to the Mediterranean. In the 19th century, the United Kingdom became the champion of a freedom of the seas once fought over by Selden against Grotius, and of course had Gibraltar in mind when it invented and helped impose the concept of unimpeded transit passage in the chapter of the Montego Bay Convention devoted to international straits (1982). It was in 2016 that the victory of Brexit supporters in the referendum brought the issue of this colonial military base, which had also become a tax haven over time, back into the spotlight. Could Her Majesty's subjects have pulled off the coup de force of transforming the Rock from a bastion for controlling traditional maritime flows into a virtual checkpoint for financial flows ?