Correlation is not causation. But this set of graphics from FT (HT: MR) may be a good place to look for the underlying factors that contributed to the victory of Leave. Analysis of data from the UK's 382 counting areas (local government districts) revealed that there were five strongly correlated indicators.
The areas with large proportion of degree-educated voters and jobs requiring degrees were the biggest votaries of Remain. In contrast, those who had never left UK, were among the strongest supporters of Leave,
In the recent London Mayoral Election, we carried out a similar analysis and found that areas where many people did not hold a passport — indicating they would not have been abroad recently — tended to yield high votes for the far-right Britain First party. The same pattern emerges here. After education and occupation, the share of people not holding a passport was the next most strongly correlated characteristic with the Leave vote.
And going against the conventional wisdom that economic integration is the path towards political integration, the Leave vote was strongest in those areas which were economically most dependent on EU, in terms of economic output exports.
Analysis of British Election Survey found that the strongest predictor of this counter-intuitive result comes from the attitudes towards immigration. Very interestingly, these are also the regions where immigration is perceived as most damaging.
Citizens of regions where immigration is perceived as damaging are much more likely to vote for Brexit. Presumably, the unifying forces of economic dependency are more than offset by those of competition for jobs from migration and by more latent suspicions of immigration (the Survey question was "‘Do you think that immigration undermines or enriches Britain’s cultural life?")
I am inclined to agree with David Goodhart that the persistent economic weaknesses, widening inequality, and the "disappearance of a once familiar industrial working class culture and the declining status of much non-graduate employment" may have increased the attachment to the symbols and benefits of national citizenship. This squares up with much of the public commentary on the support base of Donald Trump, Front National, Five Star Movement, and others across Western Europe.
This goes back to a theme that I have written about on numerous occasions. A robust national social safety net which assures a basic dignified human life consistent with the country's economic and social development is an absolute necessity to pacify the losers from globalization and liberalization and thereby prevent populist backlashes. This is as much sound politics as it is economics. And there are very few such areas where there is political and economic convergence.