American multinational advertising agencies first made inroads into the British advertising industry in the early twentieth century. Some were pioneers, but most came to Britain to service the advertising of American–based multinational companies. Their impact on British advertising was significant, particularly from 1945 until the late 1970s, years when American multinational agencies dominated the top end of the business. The British staged a major counter-challenge in both the British and American markets in the early 1980s, however, with considerable success. The basis of the British challenge was improved access to capital, which permitted expansion through acquisition, rather than the servicing of British–based multinational companies. Professor West places these developments in the context of multinational enterprise theory, using new data and evidence drawn largely from trade sources.