2015 United Kingdom general election

The key dates were:

As of 9 April 2015, the deadline for standing for the general election, the Electoral Commission's Register of Political Parties included 428 political parties registered in Great Britain,[22] and 36 in Northern Ireland.[23] Candidates who did not belong to a registered party could use an "independent" label, or no label at all.

The Conservative Party and the Labour Party had been the two biggest parties since 1922, and had supplied all UK prime ministers since 1935. Polls predicted that these parties would together receive between 65% and 75% of votes, and would together win between 80% and 85% of seats;[24][25] and that, as such, the leader of one of those parties would be the prime minister after the election. The Liberal Democrats had been the third party in the UK for many years; but as described by various commentators, other parties had risen relative to the Liberal Democrats since the 2010 election.[26][27] The Economist described a "familiar two-and-a-half-party system" (Conservatives, Labour, and the Liberal Democrats) that "appears to be breaking down" with the rise of the United Kingdom Independence Party (UKIP), the Greens and the Scottish National Party (SNP).[28] Newsnight[29] and The Economist[30] described the country as moving into a six-party system, with the Liberal Democrats, SNP, UKIP and Greens all being significant. Ofcom, in their role regulating election coverage in the UK, ruled that, for the general election and local elections in May 2015, the major parties in Great Britain were the Conservatives, Labour and Liberal Democrats, with UKIP a major party in England and Wales, the SNP a major party in Scotland, and Plaid Cymru (PC) in Wales, and that the Greens were not a major party.[31] The BBC's guidelines were similar but excluded UKIP from the category of "larger parties" in Great Britain, and instead stated that UKIP should be given "appropriate levels of coverage in output to which the largest parties contribute and, on some occasions, similar levels of coverage".[32][33] Seven parties (Conservative, Labour, Liberal Democrat, UKIP, SNP, PC and Green) participated in the election leadership debates.[34] Political parties based in Northern Ireland were ignored, despite the DUP being the fourth largest party in the UK in the previous election, in terms of seats won, and gaining the same number of seats as the Liberal Democrats in this election.

The Conservative Prime Minister David Cameron stood for a second term in office.

Ed Miliband was leader of the opposition and leader of the Labour Party after winning a leadership election against his brother David Miliband.

Nick Clegg and the Liberal Democrats showed a great fall in the polls after entering a coalition government with the Conservatives.

UK Independence Party leader Nigel Farage stood in the South Thanet constituency.

Nicola Sturgeon is the fifth First Minister of Scotland and the leader of the Scottish National Party, in office since 2014. She is the first woman to hold either position.

Natalie Bennett, leader of the Green Party of England and Wales. She contested Holborn and St Pancras.

Several parties operate in specific regions only. The main national parties, standing for seats across all (or most of) the country, are listed below in order of seats being contested:

• Conservative Party: led by David Cameron, the prime minister. The Conservative Party was the larger party in the coalition government, having won the most seats (306) at the 2010 election. The party stood in 647 seats (every seat except for two in Northern Ireland and the Speaker's seat).
• Labour Party: led by Ed Miliband, the leader of the opposition. Labour had been in power from 1997 to 2010. The party constituted Her Majesty's Most Loyal Opposition (also called the Official Opposition) after the 2010 election, having won 258 seats. It stood in 631 constituencies,[n 2] missing only the Speaker's seat. The Labour Party does not stand candidates for election in Northern Ireland.
• Liberal Democrats: led by Nick Clegg, the deputy prime minister. The Liberal Democrats were the junior member of the 2010–15 coalition government, having won 57 seats. They contested the same 631 seats as the Labour Party. The party did not stand candidates in Northern Ireland.
• UK Independence Party (UKIP): led by Nigel Farage, a Member of the European Parliament, who had not previously been in parliament but was standing in South Thanet in the general election. UKIP won the fourth-most votes at the 2010 election, but failed to win any seats. It subsequently won two seats at by-elections in 2014—both having been sitting Conservative MPs who resigned from the party, stood down voluntarily from their seat to fight a by-election, and won it for their new party - and won the highest share of votes at the 2014 European elections. It contested 624 seats across the United Kingdom.[n 3]
• Green parties: three distinct but co-operating Green parties operate in the UK: the Green Party of England and Wales (GPEW), the Green Party of Northern Ireland and the Scottish Green Party. The Green Party of England and Wales was led by Natalie Bennett, who had not previously been elected to Westminster, but stood in Holborn and St Pancras at the general election. The GPEW won the fourth-largest share of votes in the 2014 European elections, ahead of the Liberal Democrats. The Green Party of Northern Ireland was led by Stephen Agnew. To date, the Green Party has made little impact in general elections in Northern Ireland, though they are generally slightly more successful in South Belfast and North Down and in local elections. The party worked closely with the other Green parties and with the Green Party of Ireland. The Scottish Green Party is co-led by Patrick Harvie MSP and councillor Maggie Chapman, neither of whom were standing for election to Westminster. Caroline Lucas was elected as the only Green MP in 2010, in which the three parties received a combined 1% of the vote and were seventh overall. The Greens stood in 573 seats.

Dozens of other minor parties stood in 2015. The Trade Unionist and Socialist Coalition, founded as an electoral alliance of socialist parties in 2010, had 135 candidates and was the only other party to have more than forty candidates.[35] Respect came into the election with one MP (George Galloway), who was elected at the 2012 Bradford West by-election, but stood just four candidates. The British National Party, which finished fifth with 1.9% of the vote for its 338 candidates at the 2010 general election, stood only eight candidates following a collapse in support.[36] 753 other candidates stood at the general election, including all independents, Scottish-based, Northern Ireland-based and Wales-based party candidates, and candidates from other parties.[36]

The main parties in Northern Ireland (which had 18 constituencies) described by Ofcom,[31] the BBC[37] and others, in order of seats won, were:

• Democratic Unionist Party (DUP): the DUP won eight seats in 2010, making it the largest Northern Ireland political party, and the fourth biggest in the UK as a whole. The party also won the 2011 Northern Ireland Assembly election, but was second in the 2014 European election. It contested 16 Northern Irish constituencies, having entered into an electoral pact with the Ulster Unionist Party in the remaining two.
• Sinn Féin: Sinn Féin won the most votes in Northern Ireland in 2010, but came second in seats, winning five constituencies. It was second in the 2011 Assembly elections, but first in the 2014 European elections. Sinn Féin follows an abstentionist policy with respect to the Commons, and has never so far taken its seats there. The party also operates in the Republic of Ireland, where it does take seats in parliament. It was standing in all 18 Northern Irish constituencies. Michelle Gildernew lost her seat in 2015, which she had held by only 4 votes in 2010, thus reducing the SF MPs from 5 to 4.
• Social Democratic and Labour Party (SDLP): the SDLP was third in terms of votes and seats in the 2010 and 2011 elections, and fourth in the 2014 European elections. Prior to dissolution, the party had three MPs. The SDLP has a relationship with the Labour Party in Great Britain, with SDLP MPs generally following the Labour whip. The party was expected to have supported Labour in the event of a hung Parliament[38] and contested all 18 constituencies at the election.
• Ulster Unionist Party (UUP): in 2010 the UUP shared an electoral alliance with the Conservative Party, and finished fourth in terms of votes in Northern Ireland, but won no seats. The party has one MEP, having placed third in the 2014 European elections. It was fourth in the 2011 Assembly elections. The UUP contested 15 seats; the party did not run in two seats because of its electoral pact with the DUP, and also did not nominate a candidate against former UUP member and incumbent independent MP Sylvia Hermon.[39]
• Alliance Party of Northern Ireland: the Alliance Party had one MP, Naomi Long, who had been elected for the first time in 2010. (Long lost her seat in 2015.) It was fifth in the 2010 election by vote share, fifth overall in 2011 and sixth in 2014. Alliance has a relationship with the Liberal Democrats in Great Britain: the party's former leader sits in the House of Lords as a Liberal Democrat, but Alliance's one MP elected in 2010 sat on the opposition benches in the Commons and not with the Liberal Democrats on the government benches. The party contested all 18 Northern Irish constituencies in 2015.

Smaller parties in Northern Ireland included Traditional Unionist Voice (standing in seven seats) and the Green Party in Northern Ireland (standing in five seats). In 2015 TUV and the Greens each held one seat in the Legislative Assembly. The North Down seat was retained by independent Sylvia Hermon. The Northern Ireland Conservatives and UKIP fielded candidates, whereas Labour and the Liberal Democrats do not contest elections in Northern Ireland.[40]

• Scottish National Party (SNP): led by Nicola Sturgeon, who is First Minister of Scotland and did not stand in the general election. The SNP only contested seats in Scotland and stood in all 59 Scottish constituencies. The party received the second-most votes in Scotland and sixth-most overall in 2010, winning six seats. It won the 2011 election to the Scottish Parliament and had a surge of support since the Scottish independence referendum in September 2014, in which it was the main political party behind the losing Yes campaign.[41] Most projections suggested that it would be the third-largest party overall after the 2015 election, in terms of seats won, overtaking the Liberal Democrats.[25]

Smaller parties in Scotland include the Scottish Libertarian Party, but none of the smaller parties make much of an impact in general elections in Scotland.

• Plaid Cymru: led by Leanne Wood, who is a member of the Welsh Assembly and did not stand in the general election. Plaid Cymru organises only in Wales, where it contested all forty Welsh constituencies. The party has three MPs and was fourth in Wales (eighth overall) by vote share in 2010, later finishing third in the 2011 Welsh Assembly elections.

Wales has a number of smaller parties which, again, do not tend to make much impact in the general elections. In 2015, the Labour Party continued to dominate Welsh politics at the general elections.

Coalitions have been rare in the United Kingdom, because the first-past-the-post system has usually led to one party winning an overall majority in the Commons. However, with the outgoing Government being a coalition and with opinion polls not showing a large or consistent lead for any one party, there was much discussion about possible post-election coalitions or other arrangements, such as confidence and supply agreements.[42]

Some UK political parties that only stand in part of the country have reciprocal relationships with parties standing in other parts of the country. These include:

• Labour (in Great Britain) and SDLP (in Northern Ireland)
• Liberal Democrats (in Great Britain) and Alliance (in Northern Ireland)
• SNP (in Scotland) and Plaid Cymru (in Wales)
  • Plaid Cymru also recommended supporters in England to vote Green,[43] while the SNP leader Nicola Sturgeon said she would vote for Plaid Cymru were she in Wales, and Green were she in England.[44] However, Sturgeon also said that, if their candidate was the most progressive, she would vote for Labour were she in England.[45]
• Green Party of England and Wales (in England and Wales), Scottish Greens (in Scotland) and the Green Party in Northern Ireland (in Northern Ireland)

On 17 March 2015 the Democratic Unionist Party and the Ulster Unionist Party agreed an election pact, whereby the DUP would not stand candidates in Fermanagh and South Tyrone (where Michelle Gildernew, the Sinn Féin candidate, won by only four votes in 2010) and in Newry and Armagh. In return the UUP would stand aside in Belfast East and Belfast North. The SDLP rejected a similar pact suggested by Sinn Féin to try to ensure that an agreed nationalist would win that constituency.[46][47][48] The DUP also called on voters in Scotland to support whichever pro-Union candidate was best placed to beat the SNP.[49]

The deadline for parties and individuals to file candidate nomination papers to the acting returning officer (and the deadline for candidates to withdraw) was 4 p.m. on 9 April 2015.[50][51][52][53] The total number of candidates was 3,971; the second-highest number in history, slightly down from the record 4,150 candidates at the last election in 2010.[36][54]

There were a record number of female candidates standing in terms of both absolute numbers and percentage of candidates: 1,020 (26.1%) in 2015, up from 854 (21.1%) in 2010.[36][54] The proportion of female candidates for major parties ranged from 41% of Alliance Party candidates to 12% of UKIP candidates.[55] According to UCL's Parliamentary Candidates UK project[56] the major parties had the following percentages of black and ethnic minority candidates: the Conservatives 11%, the Liberal Democrats 10%, Labour 9%, UKIP 6%, the Greens 4%.[57] The average age of the candidates for the seven major parties was 45.[56]

The youngest candidates were all aged 18: Solomon Curtis (Labour, Wealden); Niamh McCarthy (Independent, Liverpool Wavertree); Michael Burrows (UKIP, Inverclyde); Declan Lloyd (Labour, South East Cornwall); and Laura-Jane Rossington (Communist Party, Plymouth Sutton and Devonport).[58][59][60] The oldest candidate was Doris Osen, 84, of the Elderly Persons' Independent Party (EPIC), who was standing in Ilford North.[59] Other candidates aged over 80 included three long-serving Labour MPs standing for re-election: Sir Gerald Kaufman (aged 84; Manchester Gorton), Dennis Skinner (aged 83; Bolsover) and David Winnick (aged 81; Walsall North).

A number of candidates—including two for Labour[61][62] and two for UKIP[63][64] – were suspended from their respective parties after nominations were closed. Independent candidate Ronnie Carroll died after nominations were closed.[65]

The Conservative manifesto committed to "a straight in-out referendum on our membership of the European Union by the end of 2017". Labour did not support this, but did commit to a referendum on "[any further] transfer of powers from Britain to the European Union". The Lib Dems also supported the Labour position, but explicitly supported the UK's continuing membership of the EU.

In relation to Scotland, the Conservative manifesto also stated "and the question of Scotland’s place in the United Kingdom is now settled". None of the three major party manifestos supported a second referendum.

The deficit, who was responsible for it and plans to deal with it were a major theme of the campaign. While some smaller parties opposed austerity,[66] the Conservatives, Labour, Liberal Democrats and UKIP all supported some further cuts, albeit to different extents.

Conservative campaigning sought to blame the deficit on the previous Labour government. Labour, in return, sought to establish their fiscal responsibility. With the Conservatives also making several spending commitments (e.g. on the NHS), commentators talked of the two main parties' "political crossdressing", each trying to campaign on the other's traditional territory.[67]

Hung Parliaments have been unusual in post-War British political history, but with the outgoing Government a coalition and opinion polls not showing a large or consistent lead for any one party, it was widely expected and predicted throughout the election campaign that no party would gain an overall majority, which could have led to a new coalition or other arrangements such as confidence and supply agreements.[29][68] This was also associated with a rise in multi-party politics, with increased support for UKIP, the SNP and the Greens.

The question of what the different parties would do in the event of a hung result dominated much of the campaign. Smaller parties focused on the power this would bring them in negotiations; Labour and the Conservatives both insisted that they were working towards winning a majority government, while they were also reported to be preparing for the possibility of a second election in the year.[69] In practice, Labour were prepared to make a "broad" offer to the Liberal Democrats in the event of a hung Parliament.[70] Most predictions saw Labour as having more potential support in Parliament than the Conservatives, with several parties, notably the SNP, having committed to keeping out a Conservative government.[71][72]

Conservative campaigning sought to highlight what they described as the dangers of a minority Labour administration supported by the SNP. This proved effective at dominating the agenda of the campaign[70] and at motivating voters to support them.[73][74][75][76] The Conservative victory was "widely put down to the success of the anti-Labour/SNP warnings", according to a BBC article[77] and others.[78] Labour, in reaction, produced ever stronger denials that they would co-operate with the SNP after the election.[70] The Conservatives and Lib Dems both also rejected the idea of a coalition with the SNP.[79][80][81] This was particularly notable for Labour, to whom the SNP had previously offered support: their manifesto stated that "the SNP will never put the Tories into power. Instead, if there is an anti-Tory majority after the election, we will offer to work with other parties to keep the Tories out".[82][83] SNP leader Nicola Sturgeon later confirmed in the Scottish leaders' debate on STV that she was prepared to "help make Ed Miliband prime minister".[84] However, on 26 April, Miliband ruled out a confidence and supply arrangement with the SNP too.[85] Miliband's comments suggested to many that he was working towards forming a minority government.[86][87]

The Liberal Democrats said that they would talk first to whichever party won the most seats.[88] They later campaigned on being a stabilising influence should either the Conservatives or Labour fall short of a majority, with the slogan "We will bring a heart to a Conservative Government and a brain to a Labour one".[89]

Both Labour and the Liberal Democrats ruled out coalitions with UKIP.[90] Ruth Davidson, leader of the Scottish Conservatives, asked about a deal with UKIP in the Scottish leaders' debate, replied: "No deals with UKIP." She continued that her preference and the Prime Minister's preference in a hung Parliament was for a minority Conservative government.[91] UKIP say they could support a minority Conservative government through a confidence and supply arrangement in return for a referendum on EU membership before Christmas 2015.[92] They also spoke of the DUP joining UKIP in this arrangement.[93] UKIP and DUP said they would work together in Parliament.[94] The DUP welcomed the possibility of a hung Parliament and the influence that this would bring them.[69] The party's deputy leader, Nigel Dodds, said the party could work with the Conservatives or Labour, but that the party is "not interested in a full-blown coalition government".[95] Their leader, Peter Robinson, said that the DUP would talk first to whichever party wins the most seats.[96] The DUP said they wanted, for their support, a commitment to 2% defence spending, a referendum on EU membership, and a reversal of the under-occupation penalty. They opposed the SNP being involved in government.[97][98] The UUP also indicated that they would not work with the SNP if it wanted another independence referendum in Scotland.[99]

The Green Party of England & Wales, Plaid Cymru and the Scottish National Party all ruled out working with the Conservatives, and agreed to work together "wherever possible" to counter austerity.[100][101][66] Each would also make it a condition of any agreement with Labour that Trident nuclear weapons was not replaced; the Green Party of England and Wales stated that "austerity is a red line".[102] Both Plaid Cymru and the Green Party stated a preference for a confidence and supply arrangement with Labour, rather than a coalition.[102][103] The leader of the SDLP, Alasdair McDonnell, said: "We will be the left-of-centre backbone of a Labour administration" and that "the SDLP will categorically refuse to support David Cameron and the Conservative Party".[104] Sinn Féin reiterated their abstentionist stance.[69] In the event the Conservatives did secure an overall majority, rendering much of the speculation and positioning moot.

The first-past-the-post system used in UK general elections means that the number of seats won is not closely related to vote share.[147] Thus, several approaches were used to convert polling data and other information into seat predictions. The table below lists some of the predictions. ElectionForecast was used by Newsnight and FiveThirtyEight. May2015.com is a project run by the New Statesman magazine.[148]

Seat predictions draw from nationwide polling, polling in the constituent nations of Britain and may additionally incorporate constituency level polling, particularly the Ashcroft polls. Approaches may or may not use uniform national swing (UNS). Approaches may just use current polling, i.e. a "nowcast" (e.g. Electoral Calculus, May2015.com and The Guardian), or add in a predictive element about how polling shifts based on historical data (e.g. ElectionForecast and Elections Etc.).[149] An alternative approach is to use the wisdom of the crowd and base a prediction on betting activity: the Spreadex and Sporting Index columns below cover bets on the number of seats each party will win with the midpoint between asking and selling price, while FirstPastThePost.net aggregates the betting predictions in each individual constituency. Some predictions cover Northern Ireland, with its distinct political culture, while others do not. Parties are sorted by current number of seats in the House of Commons:

(including 18 NI seats)

Other predictions were published.[157] An election forecasting conference on 27 March 2015 yielded 11 forecasts of the result in Great Britain (including some included in the table above).[158] Averaging the conference predictions gives Labour 283 seats, Conservatives 279, Liberal Democrats 23, UKIP 3, SNP 41, Plaid Cymru 3 and Greens 1.[159] In that situation, no two parties (excluding a Lab-Con coalition) would have been able to form a majority without the support of a third. On 27 April, Rory Scott of the bookmaker Paddy Power predicted Conservatives 284, Labour 272, SNP 50, UKIP 3, and Greens 1.[160] LucidTalk for the Belfast Telegraph predicted for Northern Ireland: DUP 9, Sinn Féin 5, SDLP 3, Sylvia Hermon 1, with the only seat change being the DUP gaining Belfast East from Alliance.[161][162]

Percentage shares of votes, as predicted in the first week of May:

An exit poll, collected by Ipsos MORI and GfK on behalf of the BBC, ITN and Sky News, was published at 10 pm at the end of voting:[177]

Parties		Seats	Change
	Conservative Party	316	10
	Labour Party	239	19
	Scottish National Party	58	52
	Liberal Democrats	10	47
	UK Independence Party	2	2
	Green Party	2	1
	Others	23	N/A
Conservatives 10 short of majority

This predicted the Conservatives to be 10 seats short of an absolute majority, although with the 5 predicted Sinn Féin MPs not taking their seats, it was likely to be enough to govern. (In the event, Michelle Gildernew lost her seat, reducing the number of Sinn Féin MPs to 4.)[178]

The exit poll was markedly different from the pre-election opinion polls,[179] which had been fairly consistent; this led many pundits and MPs to speculate that the exit poll was inaccurate, and that the final result would have the two main parties closer to each other. Former Liberal Democrat leader Paddy Ashdown vowed to "eat his hat" and former Labour "spin doctor" Alastair Campbell promised to "eat his kilt" if the exit poll, which predicted huge losses for their respective parties, was right.[180]

As it turned out, the results were even more favourable to the Conservatives than the poll predicted, with the Conservatives obtaining 330 seats, an absolute majority.[181] Ashdown and Campbell were presented with hat- and kilt-shaped cakes (labelled "eat me") on BBC Question Time on 8 May.[180]

Polling results for the 2015 UK general election, compared to the actual result

With the eventual outcome in terms of both votes and seats varying substantially from the bulk of opinion polls released in the final months before the election, the polling industry received criticism for their inability to predict what was a surprisingly clear Conservative victory. Several theories have been put forward to explain the inaccuracy of the pollsters. One theory was that there had simply been a very late swing to the Conservatives, with the polling company Survation claiming that 13% of voters made up their minds in the final days and 17% on the day of the election.[182] The company also claimed that a poll they carried out a day before the election gave the Conservatives 37% and Labour 31%, though they said they did not release the poll (commissioned by the Daily Mirror) on the concern that it was too much of an outlier with other poll results.[183]

However, it was reported that pollsters had in fact picked up a late swing to Labour immediately prior to polling day, not the Conservatives.[184] It was reported after the election that private pollsters working for the two largest parties actually gathered more accurate results, with Labour's pollster James Morris claiming that the issue was largely to do with surveying technique.[185] Morris claimed that telephone polls that immediately asked for voting intentions tended to get a high "Don't know" or anti-government reaction, whereas longer telephone conversations conducted by private polls that collected other information such as views on the leaders' performances placed voters in a much better mode to give their true voting intentions. Another theory was the issue of 'shy Tories' not wanting to openly declare their intention to vote Conservative to pollsters.[186] A final theory, put forward after the election, was the 'Lazy Labour' factor, which claimed that Labour voters tend to not vote on polling day whereas Conservative voters have a much higher turnout.[187]

The British Polling Council announced an inquiry into the substantial variance between the opinion polls and the actual election result.[188][189] The inquiry published preliminary findings in January 2016, concluding that "the ways in which polling samples are constructed was the primary cause of the polling miss".[190] Their final report was published in March 2016.[191]

The British Election Study team have suggested that weighting error appears to be the cause.[192]

One result of the 2015 general election was that a different political party won the popular vote in each of the countries of the United Kingdom.[199] This was reflected in terms of MPs elected: The Conservatives won in England with 319 MPs out of 533 constituencies,[200] the SNP won in Scotland with 56 out of 59,[201] Labour won in Wales with 25 out of 40,[202] and the Democratic Unionist Party won in Northern Ireland with 8 out of 18.[203]

Conservative—70–80%   Conservative—60–70%   Conservative—50–60%   Conservative—40–50%   Conservative—<40%

Labour—80–85%   Labour—70–80%   Labour—60-70%   Labour—50–60%   Labour—40–50%   Labour—<40%

Despite most opinion polls predicting that the Conservatives and Labour were neck and neck, the Conservatives secured a surprise victory after having won a clear lead over their rivals and incumbent Prime Minister David Cameron was able to form a majority single-party government with a working majority of 12 (in practice increased to 15 due to Sinn Féin's four MPs' abstention). Thus the result bore resemblance to 1992.[204] The Conservatives gained 38 seats while losing 10, all to Labour; Employment Minister Esther McVey, in Wirral West, was the most senior Conservative to lose her seat. Cameron became the first Prime Minister since Lord Salisbury in 1900 to increase his popular vote share after a full term, and is sometimes credited as being the only Prime Minister other than Margaret Thatcher (in 1983) to be re-elected with a greater number of seats for his party after a 'full term'[n 4].[205]

A map of the results, showing each constituency as a hexagon of equal size, with the black lines showing separations in regions

The Labour Party polled below expectations, winning 30.4% of the vote and 232 seats, 24 fewer than its previous result in 2010—even though in 222 constituencies there was a Conservative-to-Labour swing, as against 151 constituencies where there was a Labour-to-Conservative swing.[206] Its net loss of seats were mainly a result of its resounding defeat in Scotland, where the Scottish National Party took 40 of Labour's 41 seats, unseating key politicians such as shadow Foreign Secretary Douglas Alexander and Scottish Labour leader Jim Murphy. Labour gained some seats in London and other major cities, but lost a further nine seats to the Conservatives, recording its lowest share of the seats since the 1987 general election.[207] Ed Miliband subsequently tendered his resignation as Labour leader.

The Scottish National Party had a stunning election, rising from just 6 seats to 56 – winning all but 3 of the constituencies in Scotland and securing 50% of the popular vote in Scotland.[201] They recorded a number of record breaking swings of over 30% including the new record of 39.3% in Glasgow North East. They also won the seat of former Prime Minister, Gordon Brown, overturning a majority of 23,009 to win by a majority of 9,974 votes and saw Mhairi Black, then a 20-year-old student, defeat Labour's Shadow Foreign Secretary Douglas Alexander with a swing of 26.9%.

The Liberal Democrats, who had been in government as coalition partners, suffered the worst defeat they or the previous Liberal Party had suffered since the 1970 general election.[208] Winning just eight seats, the Liberal Democrats lost their position as the UK's third party and found themselves tied in fourth place with the Democratic Unionist Party of Northern Ireland in the House of Commons, with Nick Clegg being one of the few MPs from his party to retain his seat. The Liberal Democrats gained no seats, while losing 49 in the process—of them, 27 to the Conservatives, 12 to Labour, and 10 to the SNP. The party also lost their deposit in 341 seats, the same number as in every general election from 1979 to 2010 combined.

The UK Independence Party (UKIP) was only able to hold one of its two seats, Clacton, gaining no new ones despite increasing its vote share to 12.9% (the third-highest share overall). Party leader Nigel Farage, having failed to win the constituency of South Thanet, tendered his resignation, although this was rejected by his party's executive council and he stayed on as leader.

In Northern Ireland, the Ulster Unionist Party returned to the Commons with two MPs after a five-year absence, gaining one seat from the Democratic Unionist Party and one from Sinn Féin, while the Alliance Party lost its only Commons seat to the DUP, despite an increase in total vote share.[209]

Ipsos MORI polling after the election suggested the following demographic breakdown:

YouGov polling after the election suggested the following demographic breakdown:

The election led to an increase in the number of female MPs, to 191 (29% of the total, including 99 Labour; 68 Conservative; 20 SNP; 4 other) from 147 (23% of the total, including 87 Labour; 47 Conservative; 7 Liberal Democrat; 1 SNP; 5 other). As before the election, the region with the largest proportion of women MPs was North East England.[213]

111 seats changed hands compared to the result in 2010 plus three by-election gains reverted to the party that won the seat at the last general election in 2010.

• Mhairi Black, Scottish National Party, elected aged 20 years 237 days.[214]

• A swing of 39.3% from Labour to the SNP was recorded in Glasgow North East.[215]

• Alasdair McDonnell of the SDLP won the seat of Belfast South on 24.5% of the vote.[216][217]

On 8 May, three party leaders announced their resignations within an hour of each other:[218] Ed Miliband (Labour) and Nick Clegg (Liberal Democrat) resigned due to their parties' worse-than-expected results in the election, although both had been re-elected to their seats in Parliament.[219][220][221][222] Nigel Farage (UKIP) offered his resignation because he had failed to be elected as MP for Thanet South, but said he might re-stand in the resulting leadership election. However, on 11 May, the UKIP executive rejected his resignation on the grounds that the election campaign had been "a great success",[223] and Farage agreed to continue as party leader.[224]

Alan Sugar, a Labour peer in the House of Lords, also announced his resignation from the Labour Party for running what he perceived to be an anti-business campaign.[225]

In response to Labour's poor performance in Scotland, Scottish Labour leader Jim Murphy initially resisted calls for his resignation by other senior party members. Despite surviving a no-confidence vote by 17–14 from the party's national executive, Murphy announced he would step down as leader on or by 16 May.[226]

Financial markets reacted positively to the result, with the pound sterling rising against the Euro and US dollar when the exit poll was published, and the FTSE 100 stock market index rising 2.3% on 8 May. The BBC reported: "Bank shares saw some of the biggest gains, on hopes that the sector will not see any further rises in levies. Shares in Lloyds Banking Group rose 5.75% while Barclays was 3.7% higher", adding: "Energy firms also saw their share prices rise, as Labour had wanted a price freeze and more powers for the energy regulator. British Gas owner Centrica rose 8.1% and SSE shares were up 5.3%." BBC economics editor Robert Peston noted: "To state the obvious, investors love the Tories' general election victory. There are a few reasons. One (no surprise here) is that Labour's threat of breaking up banks and imposing energy price caps has been lifted. Second is that investors have been discounting days and weeks of wrangling after polling day over who would form the government – and so they are semi-euphoric that we already know who's in charge. Third, many investors tend to be economically Conservative and instinctively Conservative."[227]

The disparity between the numbers of votes and the number of seats obtained by the smaller parties gave rise to increased calls for replacement of the 'first-past-the-post' voting system with a more proportional system. For example, UKIP had 3.9 million votes per seat, whereas SNP had just 26,000 votes per seat, about 150 times greater representation for each vote cast. It is worth noting, however, that UKIP stood in 10 times as many seats as the SNP. Noting that UKIP's 13% share of the overall votes cast had resulted in the election of just one MP, Nigel Farage argued that the UK's voting system needed reforming, saying: "Personally, I think the first-past-the-post system is bankrupt."[228]

Re-elected Green Party MP Caroline Lucas agreed, saying: "The political system in this country is broken [...] It's ever clearer tonight that the time for electoral reform is long overdue, and it's only proportional representation that will deliver a Parliament that is truly legitimate and better reflects the people it is meant to represent."[229]

Following the election, The Daily Telegraph detailed changes to Wikipedia pages made from computers with IP addresses inside Parliament raising suspicion that "MPs or their political parties deliberately hid information from the public online to make candidates appear more electable to voters" and a deliberate attempt to hide embarrassing information from the electorate.[230]

On 21 December 2015, the UK Information Commissioner's Office fined the Telegraph Media Group £30,000 for sending 'hundreds of thousands of emails on the day of the general election urging readers to vote Conservative ... in a letter from Daily Telegraph editor Chris Evans, attached to the paper's usual morning e-bulletin'. The ICO concluded that subscribers had not expressed their consent to receive this kind of direct marketing.[231]

Four electors from Orkney and Shetland lodged an election petition on 29 May 2015 attempting to unseat Alistair Carmichael and force a by-election[232][233] over what became known as 'Frenchgate'.[234] The issue centred around the leaking of a memo from the Scotland Office about comments allegedly made by the French ambassador Sylvie Bermann about Nicola Sturgeon, claiming that Sturgeon had privately stated she would "rather see David Cameron remain as PM", in contrast to her publicly stated opposition to a Conservative government.[235] The veracity of the memo was quickly denied by the French ambassador, French consul general and Sturgeon.[236] At the time of the leak, Carmichael denied all knowledge of the leaking of the memo in a television interview with Channel 4 News.[237] but after the election Carmichael accepted the contents of the memo were incorrect, admitted that he had lied, and that he had authorised the leaking of the inaccurate memo to the media after a Cabinet Office enquiry identified Carmichael's role in the leak. On 9 December, an Election Court decided that although he had told a "blatant lie" in a TV interview, it had not been proven beyond reasonable doubt that he had committed an "illegal practice" under the Representation of the People Act[238] and he was allowed to retain his seat.[239]

At national party level, the Electoral Commission fined the three largest parties for breaches of spending regulations, levying the highest fines since its foundation:[240] £20,000 for Labour in October 2016,[241] £20,000 for the Liberal Democrats in December 2016,[242] and £70,000 for the Conservative Party in March 2017.[243][240]

The higher fine for the Conservatives reflected both the extent of the wrongdoing (which extended to the 2014 parliamentary by-elections in Clacton, Newark and Rochester and Strood) and 'the unreasonable uncooperative conduct by the Party'.[244][240] The commission also found that the Party Treasurer, Simon Day, may not have fulfilled his obligations under the Political Parties, Elections and Referendums Act 2000 and referred him for investigation to the Metropolitan Police Service.[245]

At constituency level, related alleged breaches of spending regulations led to 'unprecedented'[243] police investigations for possible criminal conduct of between 20 and 30 Conservative Party MPs. On 9 May 2017, the Crown Prosecution service decided not to prosecute the vast majority of suspects, saying that "in order to bring a charge, it must be proved that a suspect knew the return was inaccurate and acted dishonestly in signing the declaration. Although there is evidence to suggest the returns may have been inaccurate, there is insufficient evidence to prove to the criminal standard that any candidate or agent was dishonest."[246] On 2 June 2017, charges were brought under the Representation of the People Act 1983 against Craig Mackinlay, who was elected Conservative MP for South Thanet in 2015, his agent Nathan Gray, and a party activist, Marion Little.[247][248] Appearing at Westminster Magistrates' Court on 4 July 2017, the three pleased not guilty and were released on unconditional bail pending an appearance at Southwark Crown Court on 1 August 2017.[249][250] The investigation of Party Treasurer Simon Day remained ongoing.[251]

In 2016–18, the European Parliament found that UKIP had unlawfully spent over €173,000 of EU funding on the party's 2015 UK election campaign, via the Alliance for Direct Democracy in Europe and the affiliated Institute for Direct Democracy. The Parliament required the repayment of the mis-spent funds and denied the organisations some other funding.[252][253][254] It also found that UKIP MEPs had unlawfully spent EU money on other assistance for national campaigning purposes during 2014-16 and docked their salaries to recoup the mis-spent funds.[255][256][257]

• Election 2015 polls and predictions
• UK Polling Report Blog
  • UK Polling Report – 2015 Election Guide
• UK 2015 Parliamentary Election Forecast

• Another hung Parliament: what next?, video from UCL Constitution Unit
• BBC Q&A on what happens if no-one wins the election

• General Election 2015 – BBC News
• General Election 2015 at the Guardian
• General Election 2015 at the Daily Telegraph

• Alliance Party of Northern Ireland: Step forward, not back
• Communist Party of Britain: 2015 Communist Party general election manifesto
• Conservative Party: Strong leadership, a clear economic plan, a brighter, more secure future
• Democratic Unionist Party: Standing Up for Northern Ireland
• English Democrats Party: Putting England First
• Green Party in Northern Ireland: For the Common Good
• Green Party of England and Wales: For the common good
• Labour Party: Britain can be better
• Liberal Democrats: Stronger economy. Fairer society. Opportunity for everyone
• Liberal Party: General election mini manifesto 2015
• Mebyon Kernow: Vote for Cornwall... and a new approach to politics
• Plaid Cymru: Working For Wales
• Scottish Green Party: An economy for the people, a society for all
• Scottish National Party: Stronger for Scotland
• Scottish Socialist Party: For an independent socialist Scotland: Standing up for Scotland's working class majority
• Sinn Féin: Equality not austerity
• Social Democratic and Labour Party: Prosperity not austerity
• Socialist Labour Party: Socialist Labour Party manifesto
• Trade Unionist and Socialist Coalition: TUSC's general election policies
• UK Independence Party: Believe in Britain
• Ulster Unionist Party: One day, one vote, one chance for change