Some Leavers claim the referendum result was not primarily about immigration, but anxiety about Britain’s perceived loss of sovereignty to the EU. In their new book, Harold D. Clarke, Matthew Goodwin (left) and Paul Whiteley draw on data about more than 150,000 voters to analyse the factors and concerns that led people to vote Leave. The mix of calculations, emotions and cues were complex, but immigration – and the personal appeal of Nigel Farage and Boris Johnson to different groups of voters – were key.

Britain is approaching the one-year anniversary of the vote for Brexit. Yet the question of why a majority of people voted to leave the European Union (EU) remains contested. Since nearly 52 per cent of the country opted for Brexit, some have argued that the vote was motivated mainly by concerns over national sovereignty, while others have pointed to an economically ‘left behind’ group of voters, or to intense concerns over immigration. In a new book published this month we contribute to this debate.

The book, Brexit: Why Britain Voted to Leave the EU, draws on twelve years’ worth of data from representative national surveys, conducted each month from April 2004 until June 2016. They probed the backgrounds and concerns of more than 150,000 voters and in June 2016 included a panel design, whereby voters were contacted a few days before the vote and right after. These data provide unprecedented insight into the Brexit vote.

Our starting point is an established literature on what shapes public attitudes toward the EU, which stresses the importance of calculations about perceived costs and benefits of being in the EU, the role of risk, emotion, leaders, and public concerns over domestic and ‘identity-related’ issues, such immigration. In short, our argument is that Brexit was not driven by ‘one factor’. The vote to leave the EU reflected what we refer to as a complex and cross-cutting mix of calculations, emotions and cues. Within this, immigration was key.

By tracking public attitudes toward EU membership over the long-term, we show how the ‘fundamentals’ of the Brexit vote did not suddenly appear in 2016 but were ‘baked in’ long ago. By examining what shaped volatility in these attitudes since 2004, we show how people’s views of the EU were strongly shaped by their assessments of how the main parties had performed on key ‘valence’ issues, but mainly immigration and the economy. If people felt anxious over migration, ‘left behind’ economically, and worried about the control of Brussels, they were significantly more likely to oppose EU membership long before David Cameron even called the referendum.

Then, as Britain trundled toward the 2016 referendum people began to assess the costs and benefits of EU membership. Crucially, a plurality accepted that Brexit would harm the economy, and probably their own finances as well. But most voters also felt that remaining in the EU would increase the risk of terrorism, harm Britain’s cultural life and erode sovereignty, while leaving the EU would mean less immigration. Identity concerns were already trumping economic self-interest. It is likely that Angela Merkel’s decision only a few months before the vote to allow large numbers of refugees into the EU sharpened this concern and entrenched a view that politicians (and the EU) were not in control of an issue that a large section of the electorate cared deeply about. For reasons that we set out in the book, Cameron’s renegotiation with the EU failed to quell these concerns.

It is worth underlining the point that people accepted Brexit was a risk, a belief Cameron and Remainers sought to amplify through their elite-focused campaign. They recognised that many voters were risk averse and carpet-bombed them with dire warnings and prophecies. When asked ahead of the vote to indicate how risky they thought leaving would be (on a scale of 0-10 where ‘0’ is ‘no risk’ and ‘10’ is ‘very risky’), 54 percent of voters assigned scores of six of greater. Playing on this notion of risk was not necessarily a ‘bad’ strategy –believing Brexit was risky was the strongest predictor of whether or not somebody voted to Remain.

But on its own the risk-based strategy was not enough, especially when set alongside the powerful and emotionally resonant case over immigration. Our findings reveal how perceptions of risk were not distributed evenly, which meant Remain were unable to cut through to key groups who would go on to vote for Brexit in large numbers. Our statistical analysis reveals people who felt negatively toward immigration, worried about a loss of control to Brussels, and had been left behind economically were much more likely to minimise the risk of Brexit. These voters felt they had nothing to lose, or were determined to force their identity concerns onto the agenda regardless.

By examining emotions, too, our book points to another problem for Remainers, who spent too much time trying to amplify the problems of Brexit at the expense of making the positive case for EU membership. After worries about the risks of Brexit, the second strongest predictor of the Remain vote were positive feelings about the EU –a driver that was not maximised by Remainers. Might things have been different if Cameron, George Osborne and Barack Obama had consistently made the positive case for Europe?

On June 23 2016 all of these dynamics came together to deliver the vote for Brexit—a choice that reflected a complex mix of calculations, emotions and cues. Immigration was key to the vote for Brexit and ran through this decision. Not only were those who felt negatively about immigration more likely to minimise the risks of Brexit but they were also significantly more likely to turnout, and then vote for Brexit in the polling booth. Immigration exerted powerful direct and indirect effects on the vote. The idea that this issue, which gave Leavers an emotional appeal that Remain’s economic pessimism could not match, was not central is misleading. Indeed, weeks before the balloting we argued that Leavers were more likely to show up at the polls because of this ‘enthusiasm gap’ –and they did.

Though Leavers were divided on how to deal with immigration, our findings also point to the important role of ‘cues’ from leaders, specifically Boris Johnson and Nigel Farage. Johnson had a particularly important effect –if you liked Boris then even after controlling for a host of other factors you were significantly more likely to vote for Brexit. Farage was less popular among the professional middle-classes but he was more popular among blue-collar workers and left behind voters, underlining how these rival messengers were able to reach into different groups of voters. When, from June 1 2016, the rival Leave camps all put the pedal down on immigration they were firmly in tune with the core driver of their vote. Neither Cameron nor Corbyn were nearly as effective for Remain. Leader cues were much stronger on the Leave side.

In conclusion, the story of why Britain voted for Brexit is straightforward. Propagated by an unlikely pair of messengers, Leave’s ‘Take Back Control’ message harnessed the emotive power of immigration, amplifying public concerns over identity and a feeling of being left behind that had been baked in long before the vote was called. These immigration fears, hitherto confined to the politically incorrect margins, not abstract concerns about a ‘democratic deficit’ or rescuing UK sovereignty from Brussels bureaucrats, do much to explain why Britain voted for Brexit.

This post represents the views of the authors and not those of the Brexit blog, nor the LSE.

Harold D. Clarke, Matthew Goodwin and Paul Whiteley are the authors of Brexit: Why Britain Voted to Leave the European Union (Cambridge: Cambridge University Press, 2017)