The Immigration (Control of Entry Through Republic of Ireland) Order 1972
This Order excludes from the operation of section 1(3) of the Immigration Act 1971 (which exempts from control passengers travelling on local journeys within the common travel area, that is to say the area comprising the United Kingdom, Channel Islands, Isle of Man and Republic of Ireland) certain persons who enter the United Kingdom through the Republic of Ireland, (Article 3). The main classes of persons are those who merely passed through the Republic of Ireland, persons requiring visas, persons who entered the Republic of Ireland unlawfully and persons who are subject to directions given by the Secretary of State for their exclusion from the United Kingdom on the ground that such exclusion is conducive to the public good.