The Brexit Referendum

On June 23, 2016, the United Kingdom held its second referendum on European membership in 41 years.^¹ The first, in 1975, had endorsed staying by 67%. The second produced the opposite answer by a 3.78-point margin: 17,410,742 votes to leave, 16,141,241 to remain.^² Turnout was 72.21% - the highest in any UK vote since 1992.

David Cameron, the Conservative prime minister who had promised the referendum in his 2015 election manifesto to settle internal party fights about Europe, had campaigned for Remain.^³ He resigned at 08:18 the next morning. Boris Johnson - who had announced for Leave four months earlier in a Daily Telegraph column, having reportedly written two columns and chosen the more politically rewarding one - had been expected to succeed him; he withdrew within a week after Michael Gove turned on him.^⁴ Theresa May, who had supported Remain quietly, became Prime Minister on July 13. 'Brexit means Brexit,' she said.^⁵

The vote split along recognizable fault lines. Northern Ireland (55.8%) and Scotland (62%) voted Remain decisively.^⁶ England (53.4% Leave) and Wales (52.5% Leave) carried the result.^⁷ London (59.9% Remain) and the major university cities voted Remain; the post-industrial Midlands and North voted Leave.^⁸ Younger voters favored Remain by roughly 2-to-1; voters over 65 favored Leave by roughly 2-to-1.^⁹ Turnout in safer-Remain seats was lower than in marginal-Leave seats.^¹⁰

The Leave campaign rested on three claims: that EU membership cost the UK £350 million a week (a figure the UK Statistics Authority called 'misleading' before, during, and after the vote), that immigration was uncontrolled, and that the UK could 'take back control' of its laws and borders.^¹¹ The Remain campaign - 'Britain Stronger in Europe' - leaned on Treasury and IMF forecasts of post-exit GDP losses.^¹² The Office of National Statistics later estimated GDP was about 5% lower by 2024 than it would have been on the central forecast trajectory had the UK remained.^¹

The withdrawal process took 1,317 days from the vote to the formal exit.^² May's deal was rejected by Parliament three times. Johnson succeeded her in July 2019, renegotiated the Withdrawal Agreement, called a snap election on December 12, won an 80-seat majority on a 'Get Brexit Done' platform, and signed the deal into law on January 23, 2020.^³ The UK left the EU at 23:00 GMT on January 31, 2020. The transition period ended December 31, 2020. The full economic and political consequences continue to play out.^⁴