Brexit was a prominent issue in the 2019 General Election campaign. 58 seats switched to the Conservatives in the 2019 General Election. Of these constituencies, 55 voted Leave in the 2016 EU referendum.

This Insight sets out how parliamentary constituencies voted in the EU Referendum and in the 2019 General Election. It also includes some polling data on individuals’ voting decisions.

How did constituencies vote in the 2016 referendum?

The result of the EU referendum was not published at the constituency level at the time. Most of the referendum results that have been broken down by constituency are estimates.

In 2017, the BBC published figures for 169 constituencies. They based this analysis on ward-level data collected after the referendum. Dr Chris Hanretty has produced the best estimates for the remainder of the 650 constituencies. He modelled the likely result based on the demographic profile of a constituency.

The combined known and estimated results indicate that a majority of people voted to Leave in 409 seats to Remain in 241 seats.

Constituency level results

The image contains three charts. These provide the constituency level results in the 2019 General Election and the 2016 EU Referendum. The first Table shows Seats one in the 2019 General Election broken down by Party and Leave/Remain. The second Table shows the change by Party and Leave/Remain. The third is a chart showing how Leave/Remain constituencies in 2016 voted by Party in 2019.

In the 2019 General Election, 294 (72%) of Leave seats were won by the Conservatives and 106 (26%) by Labour. All the seats won by the SNP and all but one of the seats won by the Liberal Democrats had voted Remain.

The Conservatives held all their Leave-voting seats and gained 55 more. The 10 seats they lost had all voted Remain. Most of the 60 seats lost by Labour (52) were constituencies that had voted to Leave. The one seat gained by Labour had voted to Remain.

Vote strength

The charts below show the strength of the vote for Leave in the EU referendum. The chart on the left shows a positive correlation between the proportion voting Leave in 2016 and the proportion voting Conservative in 2019. The chart only shows seats won by the Conservatives.

The chart on the right compares the Labour vote in 2019 with the support for Leave in the 2016. It only shows seats won by Labour in 2019.

The Labour chart shows more or less the opposite pattern to the Conservative one. The strongest Labour vote shares were generally observed in Remain seats.

The seats that turned from Labour to the Conservatives in 2019 were mainly ones which had voted to Leave (the third chart). The 2017 Labour vote share was comparatively low in these constituencies.

The image contains three scatter charts.
Chart 1: the seats that voted more strongly to Leave in 2016 tended to have a higher share of people voting Conservative in 2019.
Chart 2: In Labour seats, more or less the opposite patter can be seen, where the Labour vote was generally stronger in Remain seats. 
Chart 3: Looking at the 2017 Labour Vote share, the seats that turned Conservative in 2019 had almost all voted Leave in 2016.

How individuals voted

In the EU referendum, 52% of individual voters voted to Leave. However, there was a majority in favour of Leave in 63% of constituencies (409 out of 650). This is due to the way that voters are clustered across the country.

Polling data can be used to look at how individuals voted. It shows a slightly different picture to the analysis above.

According to YouGov, three quarters (74%) of people who voted Leave in the referendum and who voted in the 2019 election voted Conservative.

Almost everyone (92%) who voted Leave and Conservative in the 2017 General Election stayed with the Conservatives in 2019.

The main difference in how people voted compared to the 2017 General Election was among Leave voters. One third of those who voted Leave and then Labour in 2017 and almost half (46%) of those who voted Leave and then Liberal Democrat in 2017 voted Conservative in 2019. These figures are estimates based on a survey of around 40,000 people. People’s answers to a survey might not always reflect who they actually voted for.

The importance of Brexit in deciding people’s votes

Polling data also helps us to understand the reasons behind people’s voting decisions. Lord Ashcroft Polls surveyed over 13,000 voters on election day. According to that data, Brexit was the third most important reason for people when choosing to vote for a particular party.

Among those who voted Conservative, it was the most important reason. For Liberal Democrat voters it was third. Among Labour and SNP voters, it did not feature in the top three reasons. For these voters, Brexit was displaced by: trust in the party; preferring the promises made; and believing the party would improve the running of the economy.

Brexit was an important reason for people to vote for a particular party. But the polling also suggests that it was not necessarily the determining factor. In most cases people would have been as keen to vote for their party of choice even if Brexit were not an issue. The majority of Conservative voters (79%) stated that they probably would have voted for the same party, even if Brexit had not been an issue. The figure was 84% among Labour voters, 87% among SNP voters, and 62% among Liberal Democrat voters.

Further Reading

About the author: Georgina Sturge is a statistical researcher specialising in social and general statistics at the House of Commons Library.

Photo: Brexit Scrabble, by Jeff Djevdet; Creative Commons Attribution 2.0 Generic (CC by 2.0)