In the United Kingdom, control over the entry of foreign citizens is exercised under the Immigration Act of 1971, and following a short account of the background to the legislation, this pamphlet outlines the new rules governing its administration that came into effect in 1983 and take into account changes in terminology introduced by the British Nationality Act of 1981. Topics dealt with are the following: right of abode; the common travel area; citizens of the Irish Republic; travel documents; medical examination; entry for temporary purposes; entry for employment or business, as persons of independent means or for marriage; and admission for settlement. Three appendices contain immigration statistics for 1962-81; a list of nationals of foreign countries who need visas to enter the United Kingdom; and the information on the British Nationality Act of 1981. (KH)