Research Case Study

Insight: Why Britain really voted to leave the European Union

Using a decade’s worth of survey data to determine why Britain voted for Brexit.

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    Economy, business, politics and society
    Global perspectives and challenges
    Technology, data and innovation

  • Lead Academic

    Professor Paul Whiteley

UK and EU flags flying in front of the houses of Parliament

Data is the key to unlocking why the UK voted for Brexit and Professor Paul Whiteley and his academic colleagues are now able to explain the driving forces behind the historic vote.

On Thursday 23 June 2016 the British electorate voted to leave the European Union with a vote of 52% to 48%. Just over nine months later, on 29 March 2017, Prime Minister Theresa May triggered Article 50, marking the start of two years of negotiations to thrash out Britain’s deal for its exit from the EU. 

Much has been said about how and why this ‘shock’ result came to pass. Now, Brexit: Why Britain voted to leave the European Union, co-authored by Professor Paul Whiteley from the Department of Government, uses over 10 years’ worth of survey data, a pre and post referendum panel survey and a unique survey of UKIP members to drill down into the real factors behind the vote and to examine its long-term consequences.

It’s being billed as the first comprehensive and objective study of the referendum.

This was underlined by former BBC journalist, political commentator and former president of YouGov Peter Kellner, who said: “Do not read 'Brexit’ – unless you want truth rather than propaganda, objectivity rather than bias, and evidence rather than prejudice.” 

Read the review of the book in The Economist and visit The Conversation to read an article based on the research.  

How do you get to the bottom of such a big question?

The study was essentially divided into three parts: the referendum campaign and the vote itself; changes in attitudes to membership over time going back to the early 2000s; and finally the consequences of Brexit for the UK economy and society.

The team used data from monthly cross section surveys of the British electorate dating back to 2004, collected as part of the Essex Continuous Monitoring Survey. They also completed a two wave panel survey, questioning the same people before and after voting day, plus a unique survey of UKIP party members.

The data was then analysed using a variety of modelling techniques to identify exactly what happened to public opinion on this issue over this period.

“It’s important to understand that the methodology used is not just fancy footwork. Robust methodology paints the fairest picture, making the study and its conclusions a more scientific and reliable exercise," added Professor Whiteley.

So, why did we vote to leave the EU?

Professor Whiteley said: “Brexit will be a constitutional change that will have implications for the world of politics and our society as a whole for a long time to come. As academics we have a role to play in scientifically analysing how and why this massive change came about.”

He attributes the electorate’s decision to a number of inter-locking things.

Membership of the European Union wasn’t delivering

The data showed that there had been enormous variations in attitudes towards the European Union over the last decade. The big picture is that people supported membership if they felt that it was delivering what they wanted – a prosperous economy, protection against crime and terrorism, control over immigration and efficient public services. If they did not feel that membership helped to deliver these things, or worse still prevented the British government from delivering them they opposed membership. Many of the latter felt ‘left behind’ by changes in society and the economy.

The recession of 2008

Professor Whiteley feels that Britain’s failure to effectively recover from the worst recession for over 70 years coloured the whole backdrop of the referendum, leaving many people feeling discontented and unrepresented.

The collapse of power in the Middle East

The series of protests, demonstrations, riots, coups and civil wars that began in 2010 across the Middle East and North Africa and have become known as the Arab Spring, created new waves of immigration into Europe. Many voters concluded that not only had successive UK governments mishandled this issue but so had the European Commission.

“Angela Merkel threw open Germany’s borders and in doing so broke a number of EU regulations. This only served to harden views on immigration across the rest of the EU and Britain. People felt they’d lost control of it, and fear and anxiety crept in as a consequence.”


In managing their economy, the EU opted for austerity – resulting in significant problems for countries including Greece and Italy. Professor Whiteley believes austerity did not work, delayed economic recovery both in Europe and Britain and stimulated euroscepticism.

The ‘Leave’ camp’s dual campaign

The study identifies a possibly unintentional advantage for the Leave campaign – the ability to mobilise two types of voters, with an official campaign and a less official grassroots campaign.

“The Leave campaign was divided. We had the official campaign led by Boris Johnson that galvanised the part of the electorate that saw themselves as respectable and conservative. Then we had the more unofficial grassroots campaign led by Nigel Farage that appeared to galvanise those that felt left behind, giving way to the populist movement,” said Professor Whiteley.

Usually a split camp weakens a campaign – this time it served it well.

What will the consequences of Brexit be?

The economy

Professor Whiteley notes that before the referendum, the then Chancellor of the Exchequer, George Osborne, issued extremely dour predictions for the effect of Brexit on the economy. These predictions went all the way to 2030.

“Quite simply we object to those predictions. The models used to make them are just not capable of forecasting that far ahead.”

Professor Whiteley also notes that Britain’s economy did not receive a boost when it joined the EU back in 1973, it merely continued along the same trend. The team then looked at what had happened to the economies of the 27 other member states when they had joined the EU at varying times over the last four decades. They found that in 20 of the 28 countries economic growth slowed after joining. In eight of the countries growth increased. But these were mainly eastern European countries who joined after the collapse of communism freeing up their economies and societies and catching up with their long-established counterparts in the west. This process known as ‘catch up’ would probably have occurred anyway even if they had not joined the EU.

“Although we appreciate the difference between joining and leaving, we think that if joining the EU didn’t make much of a difference to our economic growth, leaving shouldn’t be as bad as we’re being told. We feel it’s clear that the predictions from the Remainers were overblown and overly negative.”


Currently there are two forms of immigration into the UK; uncontrolled immigration from the EU and controlled immigration from outside. Professor Whiteley’s study noted that net migration into Britain had grown sharply in recent years for both types and they are currently rather similar in size. Therefore it has been argued that controlling EU immigration after Brexit will be very difficult if it cannot be controlled from outside the EU. However, there is a key difference between the two types of immigration revealed by the modelling. Immigration from the EU is largely economic based on job-seeking, something which is much less true of immigration from outside the EU. If the Home Office successfully applies restrictions on economic migration across the board post Brexit, then the numbers would come down from the EU.

The fragmentation of British politics

Professor Whiteley is monitoring the polls in the current election campaign and is finding them dynamic and ever changing. Elections results used to be based around the electorate’s strong allegiance to a particular party. But now this is fragmenting and the party system is fragmenting as weakening party attachments produce large scale volatility in electoral behaviour.

“The party system is coming unglued. This is important because a fragmented system makes it harder to govern and makes policymaking and planning much more difficult – and therein lies the serious consequences of populism, something there is still significant problem for in the UK,” he said.