Maritime empires are based on ports, many of them beyond the bounds of formal empire, or only latterly incorporated into it. Such ports might be described as bridgeheads – base areas for deeper incursions into indigenous societies. In practice, of course, the greatest benefit was often derived from the bridgehead itself. Securing those ports in ways favourable to trade on British terms required a broad repertoire of techniques and a range of collaborators subject to varying degrees of state influence and control. Ronald Robinson’s ‘ideal prefabricated collaborator’ – the settler – was a vital agent even beyond the world of formal colonisation. To take one example, British community identity, preserved and manifested in Buenos Aires, underpinned the power of British merchants to protest against, and influence Argentine government policy. Michael Reimer’s Colonial Bridgehead: Government and Society in Alexandria, 1807–1882 (1997) examined a different process, which saw incremental accretions to the power of a transnational foreign power base in the decades up to 1882. Sanitation and public order concerns led to the establishment of transnational bodies which arrogated, in part to consular control, the sovereignty of the Alexandrian authorities. The petty regimes established in the Chinese treaty ports took this process a step further. Partly based on precedents for foreign sojourner self-regulation in Qing imperial practice, small municipal administrations developed in the concessions and settlements of China as ports were opened to foreign trade and residence. As well as some absurdly tiny outposts there were British Municipal Administrations with tax-raising powers and a full panoply of municipal services in Hankou and Tianjin; Britons dominated an International Settlement administration at Xiamen (Amoy). But Britain’s Chinese jewel was Shanghai. The city’s International Settlement shared control of the city with a French concession and Chinese municipal structures but overshadowed this competition, dominating China’s biggest and most important port city and gateway to the world. Britons controlled the settlement. This essay looks at the settlement administration: the Shanghai Municipal Council (SMC), and its Shanghai Municipal Police force (SMP).

British informal imperialism in China developed a range of specific techniques for maintaining the new system set up after 1842. That year the Treaty of Nanjing opened the first treaty ports to foreign trade and residence, ceded the island of Hong Kong in perpetuity to Britain, introduced extraterritoriality and allowed for the posting of British consuls to the open ports working under a Superintendent of Trade in Hong Kong.