Recent interest in the early-modern British composite state has neglected Hanover, despite evidence of frequent and informal co-operation between the countries in foreign affairs. This article explores one aspect of diplomacy with particular import for the British–Hanoverian union, British policy in North Africa, and finds a greater degree of integration in trade policy than has been hitherto recognized. Britain's government came to recognize and treat Hanoverians in Morocco as British subjects during the eighteenth century, a policy which was expanded to the rest of North Africa and elsewhere after the acquisition of the maritime state of East Friesland at the Congress of Vienna increased the Hanoverian government's commercial responsibilities beyond its ability to cope. British policy did not reflect a consensus, and it was criticized by some who regarded Hanover as an entirely foreign state beyond the purview of the British government. But British sponsorship of Hanoverian trade prevailed over such dissent until the union's end, so that Britain's experience of composite statehood lasted until 1837.