| UK Independence Party |
UKIP |
Formed 3 September 1993. Registered 25 February 1999. Preceded by the Anti-Federalist League. MNIS Party ID 35. Electoral Commission ID PP84 (NI), PP85 (GB). |
| UK Unionist Party |
UKUP |
Formed 1995. Registered 14 January 1999. Dissolved 2008. MNIS Party ID 39. Electoral Commission ID PP107 (NI). |
| Ulster Popular Unionist Party |
UPUP |
Formed 1980. Dissolved 1995. MNIS Party ID 36. |
| Ulster Unionist Party |
UUP |
Formed 3 March 1905. Registered 14 January 1999. Preceded by Irish Unionist Alliance. MNIS Party ID 38. Electoral Commission ID PP83. |
| Unionist |
Unionist |
|
| Union Movement |
UM |
Formed 1948. Dissolved 1973. Preceded by British Union of Fascists. Succeeded by National Front (merger). |
| United Ulster Unionist Council |
UUUC |
Formed January 1974. Dissolved 1977. Electoral agreement between the Ulster Unionist Party, the Democratic Unionist Party and the Vanguard Unionist Progressive Party. |
| Unity |
Un |
Political label used by Nationalist Westminster candidates in border areas in the 1960s - 1970s. MNIS Party ID 20. |