[351] .... 'Imperialism of free trade' entered the lexicon of British historiography more than half a century ago; .... For the first half of the 19th century Britain's expansion in the world has been linked to opportunities for trade: the need either for materials to feed the growth of industry or, more frequently, for markets for its manufacturers upon whose profits the prosperity of the nation increasingly depended. Thus when recession loomed or when conditions for international trade deteriorated, government responded to effective lobbies or to the need to alleviate social distress and avoid unrest by taking a more active role in breaking down such barriers to unimpeded enterprise abroad as state monopolies or protective tariffs and in guarding