On June 23, the UK will vote on whether to remain in the EU. On November 8, the US will vote on whether to elect Donald Trump as president. These elections have much in common. Both could lead to outcomes that would have seemed inconceivable not long ago. Both pit angry populists against the political establishment. And in both cases, polling suggests that the outcome is in doubt, with prediction markets suggesting a probability of between one in four and one in three of the radical outcome occurring.

It is interesting to contrast the way that financial markets are reacting to these uncertainties. The markets are highly sensitive to Brexit news: the pound and the British stock market move with every new opinion poll. Analysis of option pricing suggests that if Britain votes to leave the EU, sterling could easily fall by more than 10 per cent and the British stock market by almost as much. It is widely believed that the uncertainties associated with Brexit are consequential enough to affect the policies of the US Federal Reserve and other major central banks.

It would in all likelihood be economically very costly for Britain to leave the EU and would raise questions about the future cohesion of the UK. It would also threaten London’s role as a financial centre and curtail British exports to Europe.