"The significance of exports in the development of the English economy in the 18th century remains controversial. Students of overseas trade have tended to emphasise the importance of exports. However, a number of authors starting with D. E. C. Eversley have stressed the importance of the home market. It is clearly the case that, in certain trades, the export market was of great significance. These include the production of woollen textiles and probably the Birmingham ‘toy’ trade. For these, continental Europe was an important market. However, for many sectors of industry, the continent was unimportant, as their main markets were the British colonies in North America and the West Indies, in some cases augmented by exports to Africa and India, and to Lisbon and Cadiz partly for re-export to Spanish and Portuguese colonies. However, the population of the British colonies, even on the eve of the American Revolution, was considerably smaller than that of the mother country, and their ability to consume British (or other) manufactures must have been proportionately smaller. The great difficulty in examining this issue is that of estimating the scale of the consumption in the home market. Except in the case of commodities that were subject to Excise, an estimate can only be made indirectly, by estimating the amount produced and adjusted that for imports and exports. The purpose of this article is to consider these issues in relation to one commodity, iron."