Briefing on 2019 General Election ERS Report

Posted on the 20th December 2019

In an election campaign characterised by uncertainty and volatility, it came as a surprise to many that the result should be such a decisive majority for one party. The Conservative Party made a net gain of 48 seats – an increase of 7.4 percentage points in their seat share compared to the 2017 general election and the largest majority for the Conservatives since 1987.

The final polls had predicted Conservative seats ranging between 311 and 367. That the difference between a hung parliament and a large majority for one party rested within a polling margin of error shows just how erratic the electoral system can be, particularly when there are more than two parties in contention.

This is an electoral system struggling to cope with increased voter volatility and multi-party politics. A system that is no longer fit for the UK.

General Election Results

United Kingdom

Due to the oddities of First Past the Post (FPTP), the Conservative Party was rewarded with a majority of seats (56.2%) on a minority of the vote (43.6%) at this election – with a 1.3 percentage point increase on its 2017 vote share giving the party a 7.4 percentage point increase in seats. The SNP also benefited disproportionately from FPTP, gaining 7.4 percent of seats in Westminster on only 3.9 percent of the vote.

While the Labour Party’s results were much more proportional, the Liberal Democrats were again disadvantaged by FPTP – the party saw an increase of 4.2 percentage points in its overall share of the vote compared with 2017, but it actually suffered a net loss of seats at this election.

Once again, smaller parties were penalised by our broken electoral system, with the Green Party only gaining one seat, despite obtaining almost three percent of the vote, and the Brexit Party not securing any representation despite getting two percent of the vote.

Party Seats % Seats % Seats Change % Votes % Votes Change
Conservative 365 56.2 +7.4 43.6 +1.3
Labour 202 31.1 -9.2 32.1 -7.9
SNP 48 7.4 +2.0 3.9 +0.8
Liberal Democrat 11 1.7 -0.2 11.5 +4.2
Plaid Cymru 4 0.6 0 0.5 0
Green Party 1 0.2 0 2.7 +1.1
Brexit Party 0 0 2.0 +2.0
Others 19 2.9 3.7


In England, the Conservatives gained an additional 49 seats; a 9.2 percentage point increase in seats (including the Speaker) for a 1.8 percent increase in votes. The Liberal Democrats lost a seat despite a 4.6 percentage point increase in votes.

The two party squeeze is most evident in England with the Conservatives and Labour taking over 98 percent of the seats and 81 percent of the votes.

Party Seats % Seats % Seats Change % Votes % Votes Change
Conservative 345 64.7 +9.2 47.2 +1.8
Labour 179 33.6 -9.0 33.9 -8.0
Liberal Democrat 7 1.3 -0.2 12.4 +4.6
Green Party 1 0.2 0 3.0 +1.2
Brexit Party 0 0 2.0 +2.0
Others 1 0.2 0 1.4


In Scotland, the SNP’s performance delivered one of the most disproportionate results with a 22 percentage point increase in seats for an 8.1 percent increase in votes. The SNP now hold 81.4 percent of the seats on 45.0 percent of the votes.

Scottish constituencies figure amongst the top ten smallest winning margins and smallest winning majorities reflecting the multi-party nature of these contests.

Party Seats % Seats % Seats Change % Votes % Votes Change
Scottish National Party 48 81.4 +22.0 45.0 +8.1
Conservative 6 10.2 -11.9 25.1 -3.5
Liberal Democrat 4 6.8 0 9.5 +2.8
Labour 1 1.7 -10.2 18.6 -8.5
Green Party 0 0 1.0 +0.8
Brexit Party 0 0 0.5 +0.5
Others 0 0 0.3 0


Wales returned one of the more proportional results for most parties except Labour who received a majority of seats for only two-fifths of the votes. However a large number of votes went unrepresented with no seats for the Liberal Democrats, Brexit Party or Green Party despite all these parties increasing their vote share.

Party Seats % Seats % Seats Change % Votes % Votes Change
Labour 22 55.0 -15.0 40.9 -8.0
Conservative 14 35.0 +15.0 36.1 +2.5
Plaid Cymru 4 10.0 0 9.9 -0.5
Liberal Democrat 0 0 0 6.0 +1.5
Brexit Party 0 0 5.4 +5.4
Green Party 0 0 0 1.0 +0.7
Others 0 0 0 0.6 0

Northern Ireland

Northern Ireland’s multi-party politics was again, as in 2017, squeezed into a more two-party shape with 83.3 percent of the seats going to just two parties despite 46.7 percent of votes going to other parties.

Northern Ireland figures quite prominently in our top ten lowest winning vote shares with two of the three lowest winning majorities, including the lowest (32.4% in South Down). As in Scotland, these small winning margins are the result of trying to force a voting system designed for two-party politics on to a multi-party system.

Party Seats % Seats % Seats Change % Votes % Votes Change
Democratic Unionist Party 8 44.4 -11.1 30.6 -5.4
Sinn Féin 7 38.9 0 22.8 -6.7
Social Democratic and Labour Party 2 11.1 +11.1 14.9 +3.1
Alliance 1 5.6 +5.6 16.8 +8.8
Ulster Unionist Party 0 0 11.7 +1.4
Others 0 0 -5.6 3.4 0


A well-established political science measure of disproportionality is the Deviation from Voting (DV), or Deviation from Proportionality, score. The DV score shows the extent to which an election result deviates from proportionality, i.e. from what it would look like under a proportional system, by giving a percentage of seats in parliament which are ‘unearned’ in proportional terms.

There are various ways of measuring DV scores – we have used the Loosemore-Hanby index, which is calculated by adding up the difference between each party’s vote share and their seat share, and dividing by two. This gives a ‘total deviation’ score – the higher the score, the more disproportionate the result. While theoretically such a score could range from 0% to 100%, this is highly unlikely. A typical proportional system will give a DV score of 5%–8%.

Area DV Index (%)
UK 16.2
England 17.5
Scotland 36.4
Wales 14.2
NI 30.0
East Midlands 27.9
East of England 32.6
London 19.0
North East 22.9
North West 13.5
South East 34.1
South West 34.6
West Midlands 21.3
Yorkshire and the Humber 18.1

The DV score for the UK is 16.2 percent, which is higher than the 9.3 percent of the 2017 election, but much more in line with the DV scores for previous elections. In the case of the 2015 general election the DV score was 24.2 percent. The prior post-war record was 23.0 percent in 1983. The DV score in 2010 was 21.8 percent.

The DV score for the UK is already quite high (16.2% of seats were ‘unearned’ at the 2019 election), but this overall score actually masks some significantly high DV scores within the nations and regions.

The DV score for England is 17.5 percent, while Scotland’s is much higher at 36.4 percent, which might be explained by the SNP’s performance in terms of seat share, compared to its share of the vote. The DV for Wales is relatively low (14.2%), while the Northern Irish is much higher (30.0%). These results indicate that over a third of seats in Scotland were ‘unearned’ in proportional terms, while slightly less than a third were unearned in NI.

Even though the DV score for England as a whole is lower than Scotland and Northern Ireland’s, there are significant differences across English regions. Around a third of seats in the South West, South East and East of England were ‘unearned’ in proportional terms, while over a quarter of seats were ‘unearned’ in the East Midlands. Around a fifth of seats were unearned in London, the North East, West Midlands and Yorkshire and the Humber. As we found in our report on the 2019 local elections in Britain, it would seem that these differences even each other out, with different parties overperforming in specific regions, leading to a lower DV score for England as a whole.

Smallest Share of the Vote Needed to Win

In seats where more than two parties were in contention, winners were elected on a small minority of the vote. The smallest of these being in South Down where the winning MP gained just 32.4 percent of the vote share – this means that over two-thirds of voters in South Down voted against the winning MP.

Overall 229 of the 650 MPs were elected on less than 50 percent of the constituency vote – 35.2 percent of all MPs.

Top ten smallest winning vote shares

Constituency Vote share (%) Winning Party
South Down 32.4 Sinn Féin
Sheffield Hallam 34.7 Labour
South Antrim 35.3 DUP
Kirkcaldy & Cowdenbeath 35.3 SNP
Ynys Môn 35.5 Conservative
East Lothian 36.2 SNP
East Dunbartonshire 37.1 SNP
Caithness, Sunderland & Easter Ross 37.2 Liberal Democrat
Hemsworth 37.5 Labour
Barnsley East 37.6 Labour

Smallest Margins of Victory

Using a winner-takes-all electoral system in single member constituencies also means that some seats are gained with tiny margins of victory (the difference between votes for the winner and those for the runner up). The difference between winning or losing this year was less than 200 votes in five constituencies.

When the margin of victory is so small, this also means a great number of voters do not get their preferred choice of candidate. In these constituencies with the smallest margins of victory, between 54 and 63 percent of votes went to losing candidates. Under STV with multi-member constituencies, a slate of MPs would be elected for each area so voters would be more likely to have their preferred choice taken into account.

Top ten smallest margins of victory

Constituency Margin (Votes) Winning Party 2nd Placed Party
Fermanagh & South Tyrone 57 Sinn Féin UUP
Bury North 105 Conservative Labour
Bedford 145 Labour Conservative
East Dunbartonshire 149 SNP Liberal Democrat
Kensington 150 Conservative Labour
Caithness, Sutherland & Easter Ross 204 Liberal Democrat SNP
Coventry North West 208 Labour Conservative
Alyn & Deeside 213 Labour Conservative
Dagenham & Rainham 293 Labour Conservative
Bolton North East 378 Conservative Labour

How Many Votes to Elect an MP?

The number of votes needed to elect an MP differed quite significantly for each party. On average, it took 38,264 votes to elect a Conservative MP, while it took 50,835 votes for a Labour MP. Strikingly, it took 865,697 votes to elect a Green Party MP and 336,038 votes for a Liberal Democrat – demonstrating how punitive First Past the Post is on parties whose votes are not concentrated in specific constituencies, but spread out across the nation. The Brexit Party did not win any seats, despite having received 642,303 votes nationwide, while it only took 25,882 votes to elect an SNP MP.

Unrepresented Voters 

A staggering number of voters saw their vote count for nothing. Across the UK, almost 14.5 million people (45.3% of all voters) cast their vote for a losing candidate. Voters in Scotland and Northern Ireland fared even worse, with the choices of 53.7 percent (Scotland) and 55.1 percent (NI) of voters going unrepresented.

Looking at the proportion of unrepresented voters by party, reveals how the voting system has treated voters of different parties unfairly.

Overall, across the UK, over half (50.6%) of Labour voters saw their votes go unrepresented, compared to just under a quarter (24.0%) of Conservative voters, with even fewer (19.7%) of Conservative voters going unrepresented in England. Supporters of parties with strength spread more evenly throughout the UK fared even worse than Labour supporters. The Liberal Democrats achieved nearly 3.7 million votes, yet 92.4 percent of their voters went unrepresented. Over 96 percent of 865,697 Green Party voters went unrepresented, while all of the Brexit Party’s 642,303 voters went unrepresented.

Voters of different parties suffered from this unfairness in different parts of the UK. Labour voters were particularly disadvantaged in the English midlands and southern England, outside of London. For example, in the East of England region, where Labour received just under 750,000 votes, fully 84.1 percent of these voters saw their vote go unrepresented, compared to just 5.3 percent of Conservative voters in the region.

In the South East of England region, the Liberal Democrats recorded just under 850,000 votes (18.2% of the total, up 7.7 points on the 2017 general election), yet saw only one MP elected (down one on the last election), with 96.3 percent of their voters in this region going unrepresented.

While on this occasion Conservative voters fared best overall in achieving representation for their votes, they still suffered in some places. In London, over half (55.2%) of Conservative voters went unrepresented, while only 17.4 percent of Labour voters did. In Scotland, voters of both the Conservatives and Labour suffered, with 80.2 percent of Conservative voters and 95.4 percent of Labour voters going unrepresented, compared to just 15.2 percent of SNP voters.

Green Party voters were shortchanged in the South West region of England, where they received 115,011 votes (3.8%, up 1.5 points on the last general election). All of these voters went unrepresented. The almost 100,000 Brexit Party voters (7.9%) in North East England suffered the same fate, with every single one of them going unrepresented.

Electoral Pacts and Tactical Voting

One of the key features of this campaign has been the focus on issues such as electoral pacts between parties and tactical voting among voters. That these issues have been such talking points is a sign of the dysfunctional nature of our electoral system. First Past The Post (FPTP) has again contributed to voters facing a narrowed choice at the ballot box.

An important moment in the campaign was the moment that Nigel Farage declared that the Brexit Party would not stand in any seat that the Conservatives won at the 2017 general election, almost half of all the seats in Britain. A matter of months earlier, the Brexit Party had won the most votes in the European Parliament election, so the party withdrawing from hundreds of seats was not a sign of a healthy democracy. The decision was driven by the desire not to be seen to ‘split the Leave vote’ and put Brexit at risk.

On the other side of the Brexit debate, the Liberal Democrats, Green Party and Plaid Cymru formed a limited agreement that saw only one of their number contest 60 seats in England and Wales. Although having a smaller impact than the Brexit Party withdrawal, this meant that voters in a number of seats were denied the chance to vote for their first-choice party.

Tactical voting is another consequence of FPTP and is also an unhealthy sign for our democracy. The premise is that a voter casts their ballot for a party other than their first choice, in an attempt to prevent a party that they really dislike from winning their seat. Given the withdrawal of the Brexit Party from so many seats, tactical voting among Remain-inclined or anti-Conservative voters was the focus of much attention. A handful of websites were set up by different organisations offering advice on which ‘Remain’ or ‘anti-Conservative’ candidate was best placed to win in particular constituencies. These websites sometimes contained contradictory advice for the same seat.

BMG polling for the ERS showed that 30 percent of voters planned to vote tactically at the election, up from 20 percent at the 2017 general election. Although a perhaps understandable reaction to the iniquities of FPTP, tactical voting is not something that voters should have to consider. They should be free to vote for their first-choice party without fear that their vote will be ‘wasted’ or that their one vote will be their only chance to influence the outcome.

Results from certain seats provide evidence of likely tactical voting taking place. For example, in Canterbury, Labour’s Rosie Duffield held onto the seat she gained from the Conservatives at the 2017 general election, with an increased majority. Overall, in South East England, the Labour vote share went down by 6.5 percentage points and the Liberal Democrat vote share went up by 7.7 percentage points. However, in Canterbury, where the previously selected Liberal Democrat candidate withdrew and recommended a vote for Duffield, the Labour vote share went up by 3.3 points and the Liberal Democrat vote share went down by 2.4 points. Conversely, in Esher and Walton (also in South East England), where it had been widely reported that the Liberal Democrats were in a position of having a chance of defeating Dominic Raab, the Foreign Secretary, the Liberal Democrat vote share went up by 27.7 points and the Labour vote share went down by 15.2 points.

Both the need for electoral pacts and tactical voting would be eliminated by a move to a proportional representation voting system. Under the ERS’ favoured system, the Single Transferable Vote (STV), voters could vote for their preferred party in the knowledge they would have a fair chance of seeing a representative of their choice elected, while knowing that if their first-choice candidate is not elected, they could still have an influence on the outcome with their second or subsequent preference votes.

Safe Seats

Another recurring feature of FPTP that was again in evidence at the election was the number of ‘safe seats’, where parties are almost certain to win. Before the election, the ERS predicted the outcome in 316 seats, fully half of all seats in Great Britain. These predictions had a 100 percent success rate. Such certainty breeds complacency among parties and leads to voters being taken for granted, with safe seats ignored during election campaigns while seats that may change hands are lavished with attention.

BMG polling for the ERS revealed that those living in seats classed as marginal received far more election literature than those seats classed as safe for one party or another. Just one in four people (25%) in safe seats reported receiving four or more election leaflets or other pieces of communication through their door compared to almost half (46%) of those in potential swing seats. Nearly three times as many people in potential swing seats (14%) reported receiving 10 or more leaflets or other pieces of communication, compared to just five percent of those in safe seats.

On average, prior to the general election, a UK constituency last changed party hands 42 years ago, with 192 seats (30% of the total) last changing hands in 1945 or earlier, and 65 seats (10% of the total) not changing hands for over a century. These ‘one-party’ constituencies mean that other parties can build up substantial vote shares in particular areas yet never achieve the representation they merit.

As with recent general elections, not many seats actually changed hands at the 2019 general election, with just 79 doing so. Although this represents a small increase on the 70 seats that changed hands at the 2017 general election, it still represents just 12 percent of seats across the UK and it is a smaller number than changed hands at either the 2015 general election (111 seats) or the 2010 general election (117 seats).

Changes in votes are not being represented by changes in the House of Commons, with two artificially inflated blocs propped up by safe seats, where many voters are locked out of having a meaningful influence on our politics.

Parliamentary representation 

This election saw 220 women elected, 33.8 percent of the total number of MPs. In the last election 208 women MPs were elected (32% of the total), up from 191 in 2015. Once again, we see only minor increases in the percentage of women. At this rate it will take another nine general elections (45 years) for women to reach parity in the Commons.

There have been some milestones however, for the first time the Labour Party and Liberal Democrats have more than 50 percent women MPs.

Number of women elected by party

Party Women (% party) Men (% party)
Conservatives 87 (23.8) 278 (76.2)
Labour 104 (51.5) 98 (48.5)
SNP 16 (33.3) 32 (66.6)
Lib Dems 7 (63.6) 4 (36.4)
Green 1 (100) 0
DUP 1 (12.5) 7 (87.5)
PC 1 (25) 3 (75)
SF 2 (28.6) 5 (71.4)
SDLP 1 (50) 1 (50)
Alliance 0 1 (100)
Speaker / 1
Totals 220 430

Even before a single vote had been cast in this year’s general election, it was clear that it would be difficult to improve women’s representation in parliament. Of the 3,320 candidates standing, there were 1,121 women – just 33.8 percent of the total. Only the Labour Party selected 50 percent women candidates.

Labour Party candidates (women 53%), Green Party candidates (women 41%), Liberal Democrat candidates (women 31%), Conservative candidates (women 30%), SNP candidates (women 34%), Plaid candidates (women 25%), Brexit Party candidates (20% women).

There is a clear relationship between the number of women candidates selected in seats (winnable ones) and the resulting gender balance in the Commons. We are calling for the government to enact section 106 of the Equality Act to ensure that parties publish diversity data for candidates who are both successful and unsuccessful in their selection processes.

Registration – The Missing Millions

This election campaign has seen a significant rise in the number of people registering to vote – 3,850,859 million applications were made from the day the election was called until the registration deadline. This figure is 31 percent higher than the 2.9 million applications made ahead of the 2017 election. This election also saw a significant number of applications being made by people aged 34 or under – 67 percent of the total.

Despite this increase, much more remains to be done to close the registration gap, especially considering that many of the new applications are likely to be duplicates. Indeed, based on the 2017 figure (36.9%), around 1.4 million of the 3.8 million applications made this year are likely to be duplicates.

As we have repeatedly highlighted, millions are still missing from the electoral register. The Electoral Commission’s report into the accuracy and completeness of the 2018 electoral registers estimated that, in Great Britain:

  • Between 8.3 and 9.4 million people were not correctly registered on the local government registers.
  • Between 4.7 and 5.6 million entries on the local government registers are inaccurate.

There are stark differences in registration levels, with younger people and renters missing from the register in far greater numbers than older, white and owner-households. Ethnicity, nationality and attitudes towards registration and voting are also correlated with lower registration levels.

Knowledge of the registration process is still not universal. Polling conducted by YouGov found that fewer than half of Britons (46%) correctly knew when the election deadline was, with around a third (32%) saying they did not know. Fourteen percent thought that they could register from about one week before the election up to election day itself.

Much more can be done to improve the accuracy and completeness of the electoral registers – at the ERS we have been calling for a ‘registration revolution’ to tackle under-registration and make registration easier and more in line with citizens’ daily lives. This would include moves towards automatic registration, such as:

  • The introduction of motor-voter laws, where people can opt in to be on the register whenever they engage with government bodies;
  • an online look-up service to see if one is already registered;
  • in the absence of moves towards more automatic registration, same-day registration or voting anywhere in a constituency could be trialled.

As the Electoral Commission pointed out, moves towards automatic or more automated registration “are feasible from a technical and operational perspective and could be implemented without radically altering the structure of the electoral registration system in the UK.”

Online Campaigning

For over a decade, pundits and journalists have been declaring each general election ‘the first social media election’. While the 2019 election was not the ‘first’ social media election, it definitely was the first nationwide poll in which social media platforms and online political campaigning more broadly were under the spotlight.

Concerns around disinformation, microtargeted ads, dark money and misuse of personal data have been increasing in the past few years, particularly in the aftermath of the 2016 EU referendum and the Cambridge Analytica scandal, which came to public attention in March 2018. At the ERS, we have been at the forefront of calls to update our analogue campaign rules so that they are fit for purpose for the digital age. But very little action has been taken to date.

Disinformation and misleading claims were once again rampant during this election campaign – from the Conservative Party rebranding one of its Twitter accounts as an official fact-checker during the leaders’ debate (a move strongly condemned by the UK’s most pre-eminent fact-checking organisation), through the Liberal Democrats’ infamous use of bar charts and polling data, to many parties masking their election material as local newspapers.

Data rights also featured during this election, with the Brexit Party being investigated for failing to answer requests for the data it holds on some voters, and the Open Rights Group threatening legal action against the Conservatives, Liberal Democrats and the Labour Party over their use of personal data.

Though exact figures are hard to obtain through Facebook’s ads library, parties and third-party campaigners spent around £5.9 million on this platform during the election campaign, broken down as follows:

Party Amount
Liberal Democrats £843,949
Conservative Party £817,928
Labour Party £539,512
Brexit Party £387,134
Green Party £25,090
Plaid Cymru £5,225

Unsurprisingly, spending varied throughout the campaign, significantly increasing in the latter stages. For example, on 9th December, the Conservative Party spent £19,558 on Facebook advertising – more than they spent during the entire first week of the campaign.

While this election has brought some much needed transparency with regards to online ads, the digital realm continues to remain a completely unregulated space. We need urgent action to protect the integrity of our elections and thus ensure public confidence in our democratic processes. As part of our work on reforming electoral law and updating our analogue-age campaign regulations, the ERS is calling for:

  • The extension of the imprint requirement to online campaign material
  • The creation of a single, public and easily searchable online database of political adverts
  • Increasing the enforcement and sanctioning powers of our regulators
  • A statutory code of practice for political parties and campaigners around online campaigning and the use of personal data
  • A comprehensive review of our electoral law, ensuring that it is updated and future-proofed for the digital age.


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