Civil Partnership and Unmarried Partner
CPA grants same-sex couples that have registered their relationship in accordance with U.K. law equal treatment under the law as married couples. As a result, changes have been made to a number of areas of law, in particular, immigration.
It is now possible for same-sex partners of U.K. nationals who are themselves not U.K. citizens, to acquire legal residency status in the U.K. and eventually citizenship. It is also possible for couples wishing to visit the United Kingdom for the express purpose of registering a civil partnership to do so.
Since 1997 it has been possible for unmarried partners both in a heterosexual and same sex relationship to gain entry to the UK using an Unmarried Partners Visa. Applications tend to be more difficult than those based on marriage as you need to show that you have been together for two years and that it is a permanent relationship.