Election Resources on the Internet: Parliamentary Elections in the   U.K. - Elections to the House of Commons
Election Resources on the     Internet:
Parliamentary Elections in the United Kingdom     - Elections to the House of Commons
by Manuel Álvarez-Rivera
A constitutional monarchy with one the world's longest lasting traditions       of rule of government by consent of the governed, the United Kingdom of Great       Britain and Northern Ireland held a general election on Thursday, May 7,       2015. Unlike in other Western European nations, all members of the lower       chamber of the U.K. Parliament, the House of Commons, are elected by the       first-past-the-post system, whose functioning is described here.
The U.K. held a referendum on the       country's membership of the European Union on Thursday, June 23, 2016. Live       referendum results will be available on EU Referendum       Results - BBC News .
Summary results compiled on the basis of constituency-level figures are available       here for the following general elections:
  
  
  
2001 to 2015 general election statistics come from official reports published       by the Electoral       Commission , and 1983-97 general election results come from U.K. House       of Commons Information Office Factsheets (which in turn use data from the Britain Votes series, originally       compiled by the late F.W.S. Craig and subsequently by Colin Rallings and       Michael Thrasher).
May 22-25, 2014 European election       results are available here , while BBC News - Vote 2014 has European election results for the U.K., in addition to results of local       elections in England and Northern Ireland, held simultaneously with the European       Parliament poll last May 22.
The Additional Member System (AMS) used in Scotland and Wales for elections       to their devolved legislatures - which were held on Thursday, May 5, 2016       - is reviewed in Elections to the Scottish Parliament       and the National Assembly for Wales .
A referendum to replace the House of Commons' first-past-the-post electoral       system with the Alternative Vote (AV) system - used to choose members of Australia's House of Representatives - was       also held throughout the U.K. on May 5, 2011. The Electoral Commission has       detailed referendum results here .
The Electoral System
The United Kingdom Parliament is composed of the Crown, that is the monarch,       the House of Lords, an appointive and hereditary upper chamber, and the popularly       elected lower chamber, the House of Commons. The latter enjoys supremacy       over the former: the House of Lords' powers, originally equal to those of       the House of Commons, were drastically reduced in 1911 and 1949 to delay       of nonmoney (non-fiscal) bills. Since 1999, most of the country's hereditary       peers are excluded from membership in the House of Lords.
As it is well known, the parliamentary system of government originated in       Great Britain, where it has gradually developed under an uncodified constitution       defined by a vast body of laws, court decisions and diverse unwritten       conventions. Under its present-day form, the leader of the party commanding       a majority in the House of Commons heads the government as prime minister,       with members of his (or her) Cabinet being likewise drawn from the majority.       The prime minister is a member of the House of Commons, as are most members       of the Cabinet. Governments require majority support in the House of Commons       to remain in office: in the event a government loses a vote of confidence       in the House of Commons, it must resign or request dissolution of Parliament.
Although formally an integral part of Parliament, the monarch - since 1952,       Queen Elizabeth II - fulfills a primarily ceremonial role, in which the Crown       represents the unity of the nation and stays above party politics. As such,       the Queen does not exercise the royal right of veto over legislation approved       by Parliament.
For general election purposes, the United Kingdom is currently divided into       650 constituencies, each of which returns one Member of Parliament (MP) to       the House of Commons, elected for a maximum term of five years. Of these,       533 are in England, 59 in Scotland, 40 in Wales and 18 in Northern Ireland.       Although these constituencies are for the most part approximately equal in       population size, there are built-in imbalances. Wales is deliberately       over-represented in the House of Commons, as was Scotland until recent times:       the establishment in 1999 of a Scottish Parliament with devolved powers has       led to a reduction of the number of Scottish constituencies. Additionally,       some rural constituencies are allowed to have population sizes well below       the national average; the option would be to create districts with very large       geographical areas. As a result, the average number of electors per constituency       for the 2001 election was 67,380, but the individual constituencies ranged       from a low of 21,706 electors in the Western Isles (in Scotland's north-western       coast) to a high of 104,431 in the Isle of Wight (located off the coast of       southern England). In fact, a vote in the former constituency was almost       five times as influential in the election of an MP than one in the latter.
Four boundary commissions - one each for England, Scotland, Wales and Northern       Ireland - are responsible for the continuous review of parliamentary constituency       boundaries. These commissions are presided by the non-partisan Speaker of       the House of Commons, and their recommendations, which are supposed to be       free of political bias, have to be approved by the House of Commons. Nonetheless,       boundary revisions in Britain have been rarely devoid of controversy.
From 1918 until 1985, parliamentary candidates were required to submit a £150 deposit, which was forfeited in the event the candidate failed       to secure one-eight (12.5%) of all valid votes. Effective in 1985, the deposit       was raised to £500 (about US $750 at April 2015 exchange rates), but       the threshold for return of the deposit was lowered to one-twentieth (5%)       of all valid votes. The government had the deposit raised supposedly to prevent       the proliferation of extremist and/or frivolous candidacies, but the main       beneficiaries of the change have been the major parties, as very few of their       candidates have lost their deposits since then. Parliamentary candidates       must also be endorsed by at least ten electors.
Each elector casts a vote for one of the candidates running for MP in his       or her constituency, and the candidate with the largest number of votes is       elected to office. This method is also known as the first-past-the-post (FPTP)       or plurality system, for all that it is required is a simple majority of       votes: an absolute majority is not a requisite for election.
The Political Parties
Mass party politics in the U.K. developed with the expansion of the electoral       franchise in the mid-19th century, when the Liberal Party       and the Conservative Party emerged as the respective successors of the Whigs       and the Tories, which had existed since the early 18th century. Liberal and Conservative governments alternated in power until World       War I, but in the years following the end of the war the Labour Party gradually       displaced the Liberals as the major challenger to the Conservatives.
Labour formed two short-lived minority governments in 1923-24 and 1929-31,       and alternated in office with the Conservatives from 1945 until 1979, when       the Conservative Party was returned to power and Margaret Thatcher became       Great Britain's first (and to date only) female prime minister. Mrs. Thatcher       held office until 1990, when she lost the confidence of Conservative MPs       and was forced to resign. John Major, who succeeded Mrs. Thatcher as party       leader and prime minister, led the Conservatives to a fourth consecutive       victory in the 1992 general election, although with a reduced parliamentary       majority. However, the events of "Black Wednesday", September 16, 1992 -       when speculative attacks on the pound sterling forced the government to leave       the European Exchange Rate Mechanism (ERM) and devalue the currency - dealt       a fatal blow to the Conservatives' reputation for competent management of       the economy. The Conservative majority in the House of Commons was gradually       eroded by a number of defections and spectacular defeats in by-elections       held to fill parliamentary vacancies, but the unpopular Major government       clung to power and chose not to hold a general election until the very last       possible moment, hoping that by then the economic recovery would turn public       opinion around. It proved to be of no avail: the 1997 general election brought       eighteen years of Conservative government to an end, and a rejuvenated Labour       Party, running on a distinctly centrist platform under the leadership of       Tony Blair, was returned to power in a landslide victory. In the 2001 general       election, Labour scored a second landslide victory, while the Conservatives       had a net gain of just one seat.
Labour went on to win an unprecedented third-term victory in the 2005 general       election, albeit with a smaller (yet substantial) parliamentary majority       and a significantly reduced popular vote lead over the Conservatives. Blair       continued in office until June 2007, when he stepped down after ten years       as head of government. Gordon Brown, who had served as chancellor of the       Exchequer (minister of finance) since 1997, succeeded Blair as prime minister.       However, in the 2010 general election, the Conservatives emerged once more       as the largest party in terms of votes and seats, well ahead of Labour but       twenty seats short of an overall majority.
There have been other parties represented in the House of Commons. Late in       the 19th century and early in the       20th, the Irish Home Rule or Nationalist Party, which demanded       the establishment of a devolved legislature for Ireland, held at times the       balance of power between Liberals and Conservatives. In the second half of       the 20th century, the Liberal Party, which had retained       a handful of seats in the House of Commons, scored significant popular vote       increases (but few seat gains) on a number of occasions, most notably in       February 1974, and again in 1983, when it formed the Alliance with the Social       Democratic Party (SDP), a breakaway from the Labour Party. However, in 1997       the Liberal Democrats - the successors of the Alliance - finally achieved       a significant breakthrough in terms of parliamentary representation, and       in the 2001 and 2005 general elections the party scored further gains both       in terms of votes and seats.
Opinion polls suggested the Liberal Democrats would make significant advances       in 2010, but these failed to materialize: instead, the party lost five seats       in the House of Commons, although its share of the vote increased slightly.       Nonetheless, the Liberal Democrats held the balance of power, and party leader       Nick Clegg immediately began negotiations with Conservative leader David       Cameron to form a new government. While a government of Labour with the Liberal       Democrats and several smaller parties remained a possibility - as it turned       out, the Liberal Democrats held parallel talks with Labour at the same time       they were negotiating with the Conservatives - Gordon Brown resigned as head       of government on May 11, 2010. David Cameron became the new prime minister       that same day, heading a coalition cabinet of the Conservatives and the Liberal       Democrats - the U.K.'s first coalition government at the national level since       1940-45 - with Nick Clegg as deputy prime minister.
The Conservative-Liberal Democrat coalition government lasted until the 2015       general election, in which Prime Minister Cameron and the Conservatives remained       in power after having secured a small parliamentary majority, while the Liberal       Democrats sank to their worst result since 1970, and were reduced to a mere       eight seats in the House of Commons.
Besides the Liberal Democrats, both the Scottish National Party (SNP) and       the Welsh nationalist Plaid Cymru (PC; Party of Wales), which advocate       independence for their respective countries, have been continuously represented       in the House of Commons since 1974; in the 2015 general election, SNP achieved       a sweeping victory in Scotland, topping the poll with an absolute majority       of votes for the first time ever, and most importantly capturing 56 of the       59 Scottish seats in the House of Commons. In Northern Ireland, Unionist       and Nationalist parties supported by that province's Protestant and Roman       Catholic communities, respectively, have been the dominant political forces.       Labour and the Liberal Democrats do not organize in Northern Ireland, while       Conservative candidates in the province have usually fared poorly. In 2001,       the Ulster Unionist Party (UUP) lost considerable ground to the more extreme       Democratic Unionist Party (DUP), while the militantly republican Sinn Fein       (SF; We Ourselves) displaced the moderate Social Democratic and Labour Party       (SDLP) as the largest Nationalist party in the province. The DUP emerged       as the largest Unionist political force in the 2005 general election, while the UUP suffered a crushing defeat, losing all but one of its seats in       Westminster; its sole remaining MP, Lady Sylvia Hermon, left the party in       2010 and subsequently won re-election as an independent candidate. Meanwhile,       the Ulster Conservatives and Unionists - New Force, an electoral alliance       of UUP with the Conservatives, won no seats in 2010, but the liberal,       non-sectarian Alliance Party won a seat in the U.K. House of Commons for       the first time. However, in the 2015 general election UUP secured two seats       by virtue of an election pact with DUP, while the Alliance Party lost the       seat it gained five years earlier.
Nonetheless, it must be noted that despite significant changes in voting       patterns over the course of the past three decades, British parliamentary       politics continue to be dominated by two major parties, in no small measure       due to the amplifying effects of the first-past-the-post electoral system.
Plurality Voting and Party       Representation
The key characteristic of the British electoral system is not how many votes       does a political party accumulate, but by how much it is ahead of the other       parties, particularly in seats held with majorities of less than 10% of the       vote, known as marginal constituencies. The outcome of a general election       is actually decided in these seats, and political parties concentrate their       efforts in retaining their own marginals, and capturing those held by their       opponents.
Although Labour, the Conservatives and the Liberal Democrats contest all       (or nearly all) constituencies in Great Britain proper, with the SNP and       PC fielding candidates for all seats in their respective countries as well,       the vast majority of seats in the House of Commons are safe constituencies,       usually won by the same party in every election with majorities of 15%-20%       of the vote or more. On the basis of official election results for England,       Wales, and Northern Ireland, and notional or estimated results for Scotland       published in the Media Guide       to the New Scottish Westminster Parliamentary Constituencies , compiled       and edited by David Denver, Colin Rallings and Michael Thrasher, the distribution       of seats in the House of Commons by political party and percentage majority       in the 2001 general election under the revised Scottish constituency boundaries       would have been as follows:
  
646
  
(The notional distribution of seats in the 2005 general election under the       revised English and Welsh constituency boundaries is available further below,       under Bias in the Electoral System? )
Plurality voting works to the advantage of the larger parties, and in most       circumstances the winning party in particular, which is usually over-represented       at the expense of third parties, and often at the expense of its major challenger       as well. Nonetheless, under first-past-the-post a major party may win more       seats than its main competitor despite receiving fewer votes than the latter,       as was the case of the British elections of 1929 and February 1974 (when       Labour won more seats but fewer votes than the Conservatives) as well as       1951 (when the Conservatives won an overall majority despite having received       fewer votes than Labour). However, the system usually amplifies the majority       attained by the winning party: in all but one general election since the       end of World War II (February 1974), a single party emerged with a clear       legislative majority, and was able to subsequently form a government.
While the electoral system in Britain tends to over-represent the larger       parties, it penalizes small and middle-sized parties. In fact, a relatively       large party whose support is evenly spread throughout the country will accumulate       far fewer seats than a comparable competitor whose support is geographically       concentrated. The most dramatic example of this kind of situation occurred       in the 1983 general election, when Labour, with 27.6% of the vote, won 209       out of 650 seats in the House of Commons, but the Liberal-SDP Alliance, with       25.4% of the vote, won just 23 seats. The problem for the Alliance was that,       generally speaking, its share of the vote did not vary significantly from       region to region: that is, most of its candidates obtained results within       a few percentage points of the national average. Although the Alliance did       score a much better than average performance in some areas of southern England       - particularly the southwest, where it pushed Labour to a distant third place       - these areas happened to be Conservative strongholds at the time, and therefore       their votes failed to translate into seats. By contrast, the Labour vote       was heavily concentrated in Scotland, Wales, and to a lesser extent in northern       England. Only eleven Alliance candidates polled less than 12.5% of the vote       and lost their deposits, but a record total of 119 Labour candidates (most       of them in southern England) had their deposits forfeited.
A more recent but equally notable example in this regard took place in the       2015 general election, in which the anti-European Union United Kingdom       Independence Party (UKIP) surged to third place with 12.6% of the vote, but       won just one seat out of 650 in the House of Commons (0.2%); even the Liberal       Democrats were able to win more seats than UKIP, despite polling fewer votes       than the latter.
If the first-past-the-post system presents considerable difficulties for       middle-sized parties like UKIP and the Liberal Democrats, it effectively       shuts out much smaller political groups, such as the far-right British National       Party (BNP) or (before 2010) the environmentalist Green Party, whose support       is usually below five percent in most constituencies. However, a small party       whose support is concentrated in a specific area can not only survive but       also thrive under the system. This is the case of Plaid Cymru in Wales. Within       the British context, the PC is decidedly small, with only 0.7% of all votes       in the 2001 election. Even in Wales, its share of the vote stood at just       14.3%. However, this vote is very unevenly spread throughout the principality,       as it is highly concentrated in a few districts where Welsh speakers are       in the majority. As a result, PC held 4 of the 40 Welsh seats in the House       of Commons, a measure of representation that stood just slightly below their       proportion of the vote. Incidentally, the case of the PC was not unique:       in Scotland, the Liberal Democrats (who otherwise have not fared particularly       well under the British electoral system) held 10 of the 72 Scottish seats,       or 13.9% of the total, on a 16.3% share of the vote. This was so because       unlike in England (or for that matter Wales), the Liberal Democrats' vote       in Scotland was highly concentrated around some areas, most notably the Scottish       Highlands and Islands. In addition, the presence of the SNP made many       parliamentary contests in Scotland four-way races, as opposed to the three-way       races that are typical of England.
The results of the 2001 general election illustrate the typical behavior       of the plurality system:
  
0.2
  
The clear beneficiary of the first-past-the-post system was Labour, which       won 412 out of 659 seats (62.5%) with only 40.7% of the popular vote, largely       at the expense of the Conservatives, the Liberal Democrats and (in Scotland)       the SNP, whose representation in the House of Commons remained substantially       below their respective shares of the vote. At the same time, the Northern       Ireland Unionist and Nationalist parties - who ran candidates solely in that       province - attained representation roughly comparable to their electoral       strength on a U.K.-wide basis, as did the Welsh nationalists.
Nonetheless, it should be noted that in the 1997 and 2001 general elections,       the Liberal Democrats significantly narrowed the once-formidable gap between       their share of the vote and their representation in the House of Commons       by concentrating their resources in key marginal constituencies where the       party (rather than Labour) stands as the main challenger to the Conservatives,       and by appealing to Labour voters in these seats to cross party lines and       cast a tactical vote in order to prevent the election of Conservative candidates.       This strategy proved successful, all the more so given the sharp decline       of the Conservatives' general election fortunes between 1997 and 2005. In       the 2005 general election, the Liberal Democrats also scored a number of       notable victories in several constituencies where the party stood as the       main challenger to Labour.
Their (now wiped out) advances from 1997 to 2005 notwithstanding, the Liberal       Democrats have been among the strongest advocates of proportional representation       (PR) in Britain. However, the two major parties (particularly the Conservatives)       remain opposed to it, on the grounds that it would lead to a proliferation       of small parties and that it would introduce difficulties in the formation       of governments, since it would be expected that most of the times no single       party could count with an overall parliamentary majority.
Before 1997, the only instance in which British governments had been willing       to consider and even implement PR had been in the case of Northern Ireland,       where the Protestant majority used the first-past-the-post system to perpetuate       itself in power, at the expense of the Roman Catholic minority, which it       had relegated to second-class status. Thus, PR was introduced in the province       to insure that Catholic-based parties would be better represented in popularly       elected bodies, and in good measure to coax the Protestant majority into       power-sharing arrangements with the Catholic minority (although the       first-past-the-post system has been retained for the election of the 18 MPs       from the province). But whereas the first goal has been achieved, the second       remained somewhat elusive until fairly recent times, given the intransigence       of some politicians on both sides of the religious divide. That the British       government was willing to implement PR in Northern Ireland but not in Great       Britain proper may have appeared to be a contradiction, but the rationale       was that Northern Ireland is different, with a distinctively problematic       situation requiring different solutions.
However, in December 1997 the Labour Party government elected the preceding       May established an Independent Commission on the Voting System "to recommend       the best alternative 'system or combination of systems' to the existing       commonly-called 'First Past the Post' system of election to the Westminster       Parliament", taking into account four requirements, namely broad proportionality;       the need for stable government; an extension of voter choice; and the maintenance       of a link between MPs and geographical constituencies.
In a report presented on October 1998, the Commission - known popularly as       the Jenkins Commission after its chairman, the late Roy Jenkins, Baron Jenkins       of Hillhead - recommended a complex, two-vote mixed system, described as       "AV Top-up", under which the majority of MPs (80-85%) would be elected on       a single-member constituency basis by the Alternative Vote (AV) system used       in Australia to choose members of the House of Representatives . In order to       "significantly reduce the disproportionality and the geographical divisiveness       which are inherent in FPTP", the remaining members (15-20%) were to be elected       on a corrective or "Top-up" basis from lists put forward in 65 multi-member       areas by political parties. The Commission also recommended that these lists       be open, thus allowing voters to either vote for a party or for an individual       candidate within a list.
Although the Labour government went on to introduce PR in Great Britain proper       both at the sub-national level - for elections to the       Scottish Parliament, the National Assembly for Wales and the London Assembly       - and at the supra-national level - for elections to the European Parliament       - both the Labour Party and the Cabinet were deeply split on the matter of       reforming the House of Commons' voting system. As a result, the Jenkins       Commission report was shelved - the party's 1997 general election manifesto       (platform) commitment to hold a referendum on the issue notwithstanding -       and Labour's 2001 general election manifesto only included a pledge to "review       the experience of the new systems and the Jenkins report to assess whether       changes might be made to the electoral system for the House of Commons".       As the Jenkins Commission report aptly put it, the political parties' "desire       to improve the electoral system has tended to vary in inverse proportion       to their ability to do anything about it"...
Bias in the Electoral System?
As it was, Labour had little incentive to switch to an electoral system which       in all likelihood would have drastically reduced its large parliamentary       majority, all the more so as the existing system appears to have placed the       Conservatives at a distinct disadvantage: lower turnout rates in Labour-held       constituencies, combined with Labour's better-than-average performance in       Conservative-Labour marginals since 1992 - a shift partly driven by       anti-Conservative tactical or cross-over voting by Liberal Democratic electors       - have allowed the party to secure a larger number of seats than its share       of the vote would otherwise allow. This apparent bias of the electoral system       prevented the Conservatives from being over-represented at the expense of       Labour in 1992 - atypically, the ratio of Conservative to Labour seats was       almost identical to the proportion of Conservative to Labour votes - while       in 1997 it contributed to amplify the Conservatives' losses, and in 2001       it prevented that party from scoring significant seat gains; in 2005, the       Conservatives increased their parliamentary representation by a substantial       number of seats (on a slightly larger share of the vote), but the electoral       system continued to work to the advantage of Labour: in England proper, the       Conservatives polled a marginally larger vote than Labour, but won considerably       fewer seats than the latter.
Moreover, it appears the recent review of parliamentary constituency boundaries       has not had much of an impact on this phenomenon. According to well-known       British political scientists Colin Rallings and Michael Thrasher, editors       of the Media       Guide to the New Parliamentary Constituencies , if the 2005 general election       had taken place under the new boundaries, Labour's 66-seat overall majority       would have only been slightly reduced to 48 seats. In England, Labour would       have won eight fewer seats, and the Conservatives would have captured an       additional twelve, but Labour would have retained a commanding 72-seat lead       over the Conservatives, despite polling slightly fewer votes than its main       adversary.
The distribution of seats in the House of Commons by political party and       percentage majority in the 2005 general election under the revised constituency       boundaries would have been as follows:
  
650
  
Nonetheless, in the wake of a 2009 MPs expenses scandal which greatly damaged       Parliament's reputation, Labour - by then trailing well behind the Conservatives       in opinion polls - revived its committment to electoral reform. In February       2010 the House of Commons overwhelmingly approved a government-sponsored       amendment to the Constitutional Reform and Governance Bill, under which voters       would be asked in a referendum (scheduled to be held in October 2011) if       they wanted to switch to the Alternative Vote (AV) system for elections to       the U.K. Parliament, or retain the existing first-past-the-post system.
Initially, it was uncertain if the referendum would actually take place,       given that the bill had yet to be approved by the House of Lords; more       importantly, the Conservatives - who remain strongly in favor of       first-past-the-post - originally were widely expected to repeal the legislation       and scrap the referendum had they won an overall parliamentary majority in       the 2010 general election. However, no single party won an absolute House       of Commons majority in the election, and not surprisingly electoral reform       emerged as a major issue in the negotiations between Conservatives and Liberal       Democrats to form a new government. In the end, the Conservatives made an       about-face and agreed to hold a referendum on AV, in order to secure a coalition       agreement with the Liberal Democrats. Under the terms of the Parliamentary       Voting System and Constituencies Act passed by Parliament in February       2011, a referendum was held the following May 5 - on the same day as local       elections in England, elections to the Scottish Parliament,       the National Assembly for Wales , and the Northern Ireland Assembly -       in which voters were asked if they wanted the U.K. to adopt the Alternative       Vote system instead of the existing first-past-the-post system for electing       Members of Parliament to the House of Commons; AV was overwhelmingly rejected,       by 13,013,123 votes against (67.9%) to 6,152,607 (32.1%) in favor, on a 42.2%       turnout rate.
Meanwhile, the Parliamentary Voting System and Constituencies Act 2011 also       included provisions to reduce the size of the House of Commons to 600 seats       (down from the current 650), while making parliamentary constituencies more       equal in size: no constituency would have an electorate under 95% or over       105% of the U.K. average, except for constituencies with an area of more       than 12,000 square kilometers (approximately 4,600 square miles), and the       sparsely populated insular constituencies of Orkney & Shetland and Na       h-Eileanan an Iar (previously the Western Isles). In addition, there would       be two constituencies in the Isle of Wight, which currently elects one MP.       The Act required that boundary commissions report to Parliament their       recommendations for revised parliamentary constituency boundaries by October       2013, but the Electoral Registration and Administration Act 2013 postponed       the date of the constituency boundary review until 2018, and the boundary       commissions ceased working on the 2013 review.
Early       estimates suggested Labour would have lost far more seats than the       Conservatives (or for that matter the Liberal Democrats) had the bill's "reduce       and equalise" provisions been in place for the 2010 general election (assuming       an identical popular vote outcome under an otherwise unchanged electoral       system), and not surprisingly the party opposed the bill in Parliament, its       previous backing of AV notwithstanding. In fact, the existing electoral system       continued to work against the Conservatives, even in victory: despite attaining       both slightly higher shares of the vote and substantially larger popular       vote leads than Labour in 2005, the Conservatives still won fewer seats in       2010 and 2015 than Labour a decade earlier.