The Social Democratic Party was a centre-left to centrist political party in the United Kingdom. It was formed in 1981 and was dissolved in 1988 when it merged with the Liberal Party to form Liberal Democrats.
This article encompasses results of historical UK general elections and European Parliament elections which the Social Democratic Party participated in.
| Year | of Candidates | Total votes | Mean votes per candidate | % UK vote | Change % +/- | Saved deposits | of MPs | |
|---|---|---|---|---|---|---|---|---|
| 1983 | 311 | 3,570,834 | 11,482 | 11.7% | New | — | 6 | |
| 1987 | 306 | 3,168,183 | 10,354 | 9.7% | 1.9% | — | 5 | |
Through by-elections during the 1979–1983 UK Parliament, the SDP succeeded in electing 2 Social Democrat MPs.
| SPD results in Parliamentary by-elections from 1981 to 1983 | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Election | Candidate | Votes | % | Position | 1979 | Result | By-election | |||||||
| LAB | LIB | CON | OTH | LAB | SDP | CON | OTH | |||||||
| 1981 Warrington by-election | 12,521 | 42.40 | 2 | 61.6 | 9.1 | 28.8 | 9.6 | LAB hold | 48.4 | 42.4 | 7.1 | 2.1 | ||
| 1981 Crosby by-election | 28,118 | 49.0 | 1 | 25.4 | 15.2 | 57.0 | 2.4 | SDP gain from CON | 9.5 | 49.1 | 39.8 | 1.6 | ||
| 1982 Glasgow Hillhead by-election | 10,106 | 33.40 | 1 | 34.4 | 14.4 | 41.0 | 10.1 | SDP gain from CON | 25.9 | 33.4 | 26.6 | 14.1 | ||
| 1982 Mitcham and Morden by-election | [1] | 9,032 | 29.40 | 2 | 45.2 | 8.9 | 43.9 | 2.0 | CON gain from LAB | 24.4 | 29.4 | 43.4 | 2.8 | |
| 1982 Gower by-election | 9,875 | 25.10 | 2 | 53.2 | 9.1 | 30.6 | 7.2 | LAB hold | 43.5 | 25.1 | 22.1 | 9.3 | ||
| 1982 Peckham by-election | 7,418 | 32.91 | 2 | 59.9 | 7.7 | 28.1 | LAB hold | 50.3 | 32.9 | 12.4 | 4.4 | |||
| 1983 Darlington by-election | 12,735 | 24.5 | 3 | 45.6 | 10.2 | 43.4 | 0.9 | LAB hold | 39.5 | 24.5 | 34.9 | 1.1 | ||
| SPD results in the 1983 general election[2] | ||||||
|---|---|---|---|---|---|---|
| Constituancy | Candidate | Votes | % | Position | Result | |
| Aberdeen North | 10,118 | 24.7 | 2nd | LAB hold | ||
| Aberdeen South | 10,372 | 26.2 | 3rd | CON hold, but SDP and LAB together outpolled them | ||
| Aldridge-Brownhills | 11,599 | 24.4 | 3rd | CON hold | ||
| Alyn and Deeside | 9,535 | 21.6 | 3rd | LAB win (new seat) | ||
| Angus East | 4,978 | 11.4 | 3rd | CON win (new seat) | ||
| Ashford | 13,319 | 27.8 | 2nd | CON hold | ||
| Ashton-under-Lyne | 7,521 | 17.8 | 3rd | LAB hold | ||
| Aylesbury | 15,310 | 29.4 | 2nd | CON hold | ||
| Banbury | 13,200 | 26.9 | 2nd | CON hold | ||
| Banff and Buchan | 6,084 | 15.0 | 3rd | CON win (new seat) | ||
| Barnsley West and Penistone | 9,624 | 21.7 | 3rd | LAB hold | ||
| Barrow and Furness | 11,079 | 21.7 | 3rd | SDP split left-wing vote allowing CON gain from LAB | ||
| Basildon | 11,634 | 25.7 | 3rd | CON hold, but SDP and LAB together outpolled them | ||
| Basingstoke | Ednyfed Hudson Davies (defecting Labour MP from Caerphilly) | 15,931 | 28.8 | 2nd | CON hold | |
| Bassetlaw | 8,124 | 16.7 | 3rd | LAB hold | ||
| Bath | 17,240 | 36.0 | 2nd | CON hold, but SDP and LAB together outpolled them | ||
| Batley and Spen | 11,678 | 21.6 | 3rd | CON win (new seat), but SDP+LAB outpolled them | ||
| Battersea | 7,675 | 17.5 | 3rd | LAB win (new seat) | ||
| South West Bedfordshire | 16,036 | 27.8 | 2nd | |||
| East Berkshire | 17,868 | 29.9 | 2nd | |||
| Birmingham Edgbaston | 8,167 | 22.4 | 2nd | |||
| Birmingham Erdington | 7,915 | 21.1 | 3rd | |||
| Birmingham Selly Oak | 10,613 | 20.7 | 3rd | |||
| Birmingham Small Heath | 5,722 | 16.0 | 3rd | |||
| Birmingham Sparkbrook | 3,416 | 10.4 | 3rd | |||
| Birmingham Yardley | 8,109 | 23.1 | 3rd | |||
| Blackburn | 8,174 | 14.4 | 3rd | |||
| Blackpool South | 9,417 | 24.0 | 3rd | |||
| Blaydon | 12,607 | 26.3 | 3rd | |||
| Blyth Valley | 13,340 | 31.8 | 2nd | |||
| Bolsover | 7,886 | 16.8 | 3rd | |||
| Bolton North East | John Alcock | 8,311 | 18.3 | 3rd | ||
| Bradford North | Peter Birkby | 11,962 | 25.5 | 3rd | ||
| Bradford West | Edward Lyons (defecting Labour MP) | 13,301 | 27.1 | 3rd | LAB hold (that is, reverted to 1979 status quo) | |
| Caithness and Sutherland | Robert Maclennan (defecting Labour MP) | 12,119 | 52.0 | 1st | SDP gain from LAB (held 1981 gain) | |
| Joseph Withnall | 11,336 | 22.1 | 3rd | |||
| Cardiff West | Jeffrey Thomas (defecting Labour MP from Abertillery) | 10,388 | 25.5 | 3rd | SDP split left-wing vote allowing CON gain from LAB | |
| Clwyd South West | Tom Ellis (defecting Labour MP from Wrexham) | 13,024 | 30.2 | 2nd | CON win in new seat; SDP+LAB together outpolled them | |
| Crosby | (sitting SDP MP) | 27,203 | 42.0 | 2nd | CON hold (that is, reverted to 1979 status quo) | |
| Darlington | Ray Dutton | 8,737 | 17.4 | 3rd | ||
| Dewsbury | David Ginsburg (defecting Labour MP) | 13,065 | 25.3 | 3rd | SDP split left-wing vote allowing CON gain from LAB | |
| Erith and Crayford | James Wellbeloved (defecting Labour MP) | 14,369 | 34.9 | 2nd | SDP split left-wing vote allowing CON gain from LAB | |
| Glasgow Hillhead | Roy Jenkins (sitting SDP MP) | 14,856 | 36.2 | 1st | SDP gain from CON (held 1982 by-election gain) | |
| Hackney South and Shoreditch | Ronald Brown (defecting Labour MP) | 7,025 | 18.3 | 3rd | LAB hold (that is, reverted to 1979 status quo) | |
| Halifax | F. Cockroft | 11,868 | 21.7 | 3rd | ||
| Hayes and Harlington | Neville Sandelson (defecting Labour MP) | 11,842 | 29.0 | 3rd | SDP split left-wing vote allowing CON gain from LAB | |
| Hyndburn | John Bridgen | 6,716 | 14.6 | 3rd | ||
| Islington North | John Grant (defecting Labour MP from abolished Islington Central) | 8,268 | 22.4 | 3rd | LAB hold (that is, reverted to 1979 status quo) | |
| Islington South and Finsbury | George Cunningham (defecting Labour MP) | 13,097 | 35.3 | 2nd | LAB hold (that is, reverted to 1979 status quo) | |
| Leicester East | Tom Bradley(defecting Labour MP) | 10,362 | 21.1 | 3rd | SDP split left-wing vote allowing CON gain from LAB | |
| Lewisham East | Polly Toynbee | 9,351 | 22.0 | 3rd | ||
| Leyton | Bryan Magee (defecting Labour MP) | 9,448 | 24.9 | 3rd | LAB hold (that is, reverted to 1979 status quo) | |
| Liverpool Broadgreen | Richard Crawshaw (defecting Labour MP from abolished Liverpool Toxteth) | 5,169 | 11.2 | 4th | LAB win in new seat | |
| Liverpool West Derby | Eric Ogden (defecting Labour MP) | 7,871 | 18.0 | 3rd | LAB hold (that is, reverted to 1979 status quo) | |
| Meriden | Pamela Dunbar | 10,674 | 20.1 | 3rd | ||
| Newcastle Central | John Horam (defecting Labour MP from abolished Gateshead West) | 9,923 | 22.3 | 3rd | SDP split left-wing vote allowing CON gain from LAB | |
| Newcastle upon Tyne East | Mike Thomas (defecting Labour MP) | 11,293 | 26.7 | 3rd | LAB hold (that is, reverted to 1979 status quo) | |
| Newham North West | Alec Kellaway | 5,204 | 18.6 | 3rd | ||
| North West Norfolk | Christopher Brocklebank-Fowler (defecting Conservative MP) | 20,211 | 37.6 | 2nd | CON hold, but SDP and LAB together outpolled them | |
| Norwich South | Charles Hardie | 11,968 | 24.5 | 3rd | ||
| Plymouth Devonport | David Owen (defecting Labour MP) | 20,843 | 44.3 | 1st | SDP gain from LAB (held 1981 gain) | |
| Renfrew West and Inverclyde (replaced West Renfrewshire) | Dickson Mabon (defecting Labour MP from abolished Greenock & Port Glasgow) | 12,347 | 29.5 | 2nd | SDP split left-wing vote allowing CON gain from LAB | |
| Ross, Cromarty and Skye (replaced Ross and Cromarty) | Charles Kennedy | 13,528 | 38.5 | 1st | SDP gain from CON | |
| Slough | Nicholas Bosanquet | 9,519 | 18.5 | 3rd | ||
| Southampton Itchen | Bob Mitchell (defecting Labour MP) | 16,647 | 31.5 | 2nd | SDP split left-wing vote allowing CON gain from LAB | |
| Stockport | Thomas McNally (defecting Labour MP from abolished Stockport South) | 12,129 | 27.6 | 3rd | SDP split left-wing vote allowing CON win in new seat | |
| Stockton North (replaced Stockton-on-Tees) | William Rodgers (defecting Labour MP) | 14,630 | 29.6 | 3rd | LAB hold (that is, reverted to 1979 status quo) | |
| Stockton South (replaced Thornaby) | Ian Wrigglesworth (defecting Labour MP) | 19,550 | 36.8 | 1st | SDP gain from LAB (held 1981 gain) | |
| Woolwich (replaced Woolwich East) | John Cartwright (defecting Labour MP) | 15,492 | 40.5 | 1st | SDP gain from LAB (held 1981 gain) | |
| Worsley | John Roper (defecting Labour MP from Farnworth) | 14,545 | 27.1 | 3rd | LAB win in new seat | |
Through by-elections during the 1983–1987 UK Parliament, the SDP succeeded in electing 2 Social Democrat MPs.
The SDP participated in the 1982, 1983, 1984, 1985, 1986, 1987 local elections.[3]