Britain's industrialisation, and her extensive overseas commercial and financial connections, meant that during the nineteenth century she played a significant role in the world economy. From a national perspective, too, international factors were of continuing importance in the development of the domestic economy. As a proportion of Gross National Product, exports of goods and services rose from over 15 per cent in the 1840s, to a peak of about 35 per cent in the 1870s, falling back only slightly to under 30 per cent just before the First World War. 1 An early technological lead helped the UK to achieve international economic hegemony as the world's leading commercial nation and, despite relatively faster growth among industrial competitors as they ‘caught up’ from the latter half of the nineteenth century, the UK remained the largest international trader at the outset of the First World War. 2 Many of the world's most important commodity markets for raw materials and foodstuffs were based in Britain and a high proportion of the world's trade was carried by Britain's growing merchant fleet. A heavy dependence on overseas raw materials and food, a free trade policy from the 1840s, and worldwide imperial connections, all ensured that the UK remained the most important single consumer of internationally–traded primary produce. Obviously, in such circumstances external trade factors were highly influential within the domestic economy and, indeed, were critical for individual manufacturing sectors such as textiles, iron and steel, and coal.