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The Ulster Unionist Party held the majority of Northern Ireland seats in most elections for the Westminster Parliament between 1922 and 2001. Since then its representation has been low or non-existent, having been eclipsed by the Democratic Unionist Party. It always had an absolute majority in the Stormont Parliament (1921–1972); since that Parliament was replaced by the Northern Ireland Assembly it has had a substantial minority representation there. Its share of the vote in Northern Ireland local government elections has tended to diminish, so that there too it is no longer the largest party. Finally, the party has always held one of the three Northern Ireland seats in the European Parliament. Its share of the Northern Ireland vote in the most recent elections to these bodies has been between 10.5% (Westminster 2017) and 16.1% (local government, 2014).
Sproule, Luke (11 May 2022). "NI election 2022: How UUP and SDLP lost their place as Northern Ireland's top parties". Retrieved 13 February 2024. The DUP said this showed Sinn Féin was unfit to be involved in government and at the 2005 general election the more hardline unionists replaced the UUP as Northern Ireland's biggest party at Westminster.
Albrecht, Annekathrin (10 March 2008). The breakout of "the troubles" - Inter-communal violence in Northern Ireland. GRIN Verlag. ISBN9783638036092. The Ulster Unionist Party (UUP) dominated Northern Irish politics from partition in 1921 until its collapse in 2005 which means that all governments form 1921 to 1972 were formed by the UUP.
"Letter: The Ulster Unionist Party cannot recover, so after 10 years I am quitting it". newsletter.co.uk. 20 May 2023. Retrieved 13 February 2024. I stood for the UUP in the 2019 council election for Comber DEA for Ards and North Down Borough Council, during which the UUP also declined as it appears to be declining again in the 2023 council election. This will now be the sixth election in a row since 2017 (Assembly: 2017, 2022; Council: 2019, 2023; Euro: 2019; Westminster: 2017) the UUP has declined, in which the party didn't decline in the 2019 Westminster election as they had no seats anyway.
"1922 Westminster Elections". www.ark.ac.uk. Retrieved 13 February 2024. Unionist 107,972 51.9% 11 MPs (Antrim (2 seats), Armagh, East Belfast, North Belfast, South Belfast, West Belfast, Down (2 Seats), Londonderry and Queens University
"1923 Westminster Elections". www.ark.ac.uk. Retrieved 13 February 2024. Unionist 117,161 48.4% 11 MPs (Antrim (2 seats), Armagh, East Belfast, North Belfast, South Belfast, West Belfast, Down (2 Seats), Londonderry and Queens University.
"1924 Westminster Elections". www.ark.ac.uk. Retrieved 13 February 2024. Unionist 451,278 86.9% 13 MPs (Antrim (2 seats), Armagh, East Belfast, North Belfast, South Belfast, West Belfast, Down (2 Seats), Fermanagh & Tyrone (2 seats), Londonderry and Queens University.
"1929 Westminster Elections". www.ark.ac.uk. Retrieved 13 February 2024. Unionist 354,657 69.5% 11 MPs (Antrim (2 seats), Armagh, East Belfast, North Belfast, South Belfast, West Belfast, Down (2 Seats), Londonderry and Queens University.
"1931 Westminster Elections". www.ark.ac.uk. Retrieved 13 February 2024. Unionist 149,566 53.0% 11 MPs (Antrim (2 seats), Armagh, East Belfast, North Belfast, South Belfast, West Belfast, Down (2 Seats), Londonderry and Queens University.
"1935 Westminster Elections". www.ark.ac.uk. Retrieved 13 February 2024. Unionist 292,840 64.9% 11 MPs (Antrim (2 seats), Armagh, East Belfast, North Belfast, South Belfast, West Belfast, Down (2 Seats), Londonderry and Queens University.
"1945 Westminster Elections". www.ark.ac.uk. Retrieved 13 February 2024. Unionist 394,373 54.6% 9 MPs (Antrim (2 seats), Armagh, East Belfast, North Belfast, South Belfast, Down (1 of 2 seats), Londonderry and Queens University.
"1950 Westminster Elections". www.ark.ac.uk. Retrieved 13 February 2024. Unionist 352,334 62.8% 10 MPs (Armagh , East Belfast, Londonderry, North Antrim, North Belfast, North Down, South Antrim, South Belfast, South Down and West Belfast)
"1951 Westminster Elections". www.ark.ac.uk. Retrieved 13 February 2024. Unionist 274,928 59.4% 9 MPs (Armagh , East Belfast, Londonderry, North Antrim, North Belfast, North Down, South Antrim, South Belfast and South Down)
"1955 Westminster Elections". www.ark.ac.uk. Retrieved 13 February 2024. Unionist 442,647 68.5% 10 MPs (Armagh , East Belfast, Londonderry, North Antrim, North Belfast, North Down, South Antrim, South Belfast, South Down and West Belfast)
"1959 Westminster Elections". www.ark.ac.uk. Retrieved 13 February 2024. Unionist 445,013 77.2% 12 MPs (Armagh , East Belfast, Fermanagh & South Tyrone, Londonderry, Mid Ulster, North Antrim, North Belfast, North Down, South Antrim, South Belfast, South Down and West Belfast)
"1964 Westminster Elections". www.ark.ac.uk. Retrieved 13 February 2024. Unionist 401,897 63.2% 12 MPs (Armagh , East Belfast, Fermanagh & South Tyrone, Londonderry, Mid Ulster, North Antrim, North Belfast, North Down, South Antrim, South Belfast, South Down and West Belfast)
"1966 Westminster Elections". www.ark.ac.uk. Retrieved 13 February 2024. Unionist 368,629 61.8% 11 MPs (Armagh , East Belfast, Fermanagh & South Tyrone, Londonderry, Mid Ulster, North Antrim, North Belfast, North Down, South Antrim, South Belfast and South Down)
"1970 Westminster Elections". www.ark.ac.uk. Retrieved 13 February 2024. Unionist 422,041 54.2% 8 MPs (Armagh , East Belfast, Londonderry, North Belfast, North Down, South Antrim, South Belfast and South Down)
"Westminster election February 1974". www.ark.ac.uk. Retrieved 13 February 2024. UUP 232,103 votes 32.3% 7 MPs (North Belfast, South Antrim, Armagh, North Down, South Down, Fermanagh and South Tyrone, and Londonderry)
"Westminster election October 1974". www.ark.ac.uk. Retrieved 13 February 2024. UUP 256,0653 votes 36.5% 6 MPs (North Belfast, South Antrim, Armagh, North Down, South Down, and Londonderry)
"Westminster election 1979". www.ark.ac.uk. Retrieved 13 February 2024. UUP 254,578 votes 36.6% 5 MPs (South Belfast, South Antrim, Armagh, South Down, and Londonderry)
"Westminster election 1983". www.ark.ac.uk. Retrieved 13 February 2024. UUP 259,952 votes 34.0% 11 MPs (North Belfast, South Belfast, East Antrim, South Antrim, South Down, Fermanagh and South Tyrone, Lagan Valley, East Londonderry, Newry and Armagh, Strangford, and Upper Bann)
"Westminster election 1987". www.ark.ac.uk. Retrieved 13 February 2024. UUP 276,230 votes 37.8% 10 MPs (North Belfast, South Belfast, East Antrim, South Antrim, Fermanagh and South Tyrone, Lagan Valley, East Londonderry, Strangford, and Upper Bann)
"Westminster election 1992". www.ark.ac.uk. Retrieved 13 February 2024. UUP 271,049 votes 34.5% 9 MPs (North Belfast, South Belfast, East Antrim, South Antrim, Fermanagh and South Tyrone, Lagan Valley, East Londonderry, Strangford, and Upper Bann)
"1997 Westminster Elections". www.ark.ac.uk. Retrieved 13 February 2024. UUP 258,439 votes 32.7% 10 MPs (North Belfast, South Belfast, East Antrim, South Antrim, Fermanagh and South Tyrone, Lagan Valley, East Londonderry, Strangford, West Tyrone, Upper Bann)
"2001 Westminster Elections". www.ark.ac.uk. Retrieved 13 February 2024. UUP 216,839 26.8% 6 MPs (South Belfast, East Antrim, South Antrim, North Down, Lagan Valley, and Upper Bann)
"The 1979 European Election". www.ark.ac.uk. Retrieved 13 February 2024. Transfers: Stage 6 The UUP's weaker candidate, West, was eliminated (Kilfedder again having a crucial margin of 3,400) and his votes were distributed between Taylor and Kilfedder as follows: 57,059.00 votes (86.6%) were transferred to his running-mate Taylor, taking him to 153,466.36 and over the quota
"The 1984 European Election". www.ark.ac.uk. Retrieved 13 February 2024. Ulster Unionist Party (John Taylor MP MEP MANI) 147,169 (21.5%)
"The 2019 European Election". www.ark.ac.uk. Retrieved 13 February 2024. Third Count - In a miserable result for the Ulster Unionist Party, Kennedy was the next to be eliminated, the first time this had happened for the UUP in a European Parliament election since 1979 (when they had two candidates).