In the maelstrom of Napoleonic Europe, Britain remained defiant, resisting French imperial ambitions. This Anglo-French rivalry was, essentially, a politico-economic conflict for pre-eminence fought on a global scale. This contest reached a zenith in 1806-1808 with French apparent dominance of Continental Europe. _x000D__x000D_Set against a backdrop of domestic political uncertainty as the much-maligned Whig Ministry of All the Talents fell from office and was replaced by a coalition of Pitt's friends, British statesmen from both sides of the political divide reacted with speed and vigour to implement maritime based strategies designed to limit French military and commercial gains in Europe, while protecting British overseas interests, which were vital to the long-term prosecution of the war and any post-war reconstruction. _x000D__x000D_This policy is particularly evident in the case of Portugal, Britain's Ancient Ally. British policy towards Portugal developed as that country came under French pressure to adhere to Napoleon's Continental System. Initially British policy considered defending mainland Portugal, then, when this was found to be far-fetched, to press for the evacuation of the Royal Family and navy to Portuguese Brazil. This, once again, opened up the potential for British intervention in South America, a thorny issue following British military embarrassment in 1806-1807. Hence, policy, in part guided by Sir Arthur Wellesley, moved away from 'realist' imperial conquest to a more liberal approach to safeguard British interests. After the Spanish uprising of May 1808, however, ministers opportunistically reassessed British strategy and decided to commit an army to expel French forces from Portugal. _x000D__x000D_Contextualising British policy towards Portugal and South America within the wider debate on the nature of British war aims and maritime strategy during the Napoleonic era, the study is an essential work for scholars of Napoleon's Wars and British political, diplomatic, economic and maritime/military history.