If the British electorate were to vote No in 2017, it would then take a year until the exit is negotiated, and another one or two years for it to become effective. So we must slightly rephrase our initial question: what is the point of the EU beyond the eurozone from 2020 onwards?

By then, I would expect the perceived importance of single market membership to have come under pressure from two sources. First, from within the eurozone. German Chancellor Angela Merkel and French President François Hollande have agreed to make a joint proposal about further eurozone economic integration in May, covering labour markets, social security and financial stability. In other words, the eurozone is starting to develop a single market within the single market.

As a loud critic of the eurozone’s crisis response, I am under no illusion about the speed of a secessionist single market. The current agreement for a banking union does not qualify. But the eurozone will ultimately end up with a proper union that covers all banks, and which includes resolution powers, deposit insurance – and usurps whatever is left of the single market for financial services.

Then there is pressure from outside the eurozone, from proponents of a transatlantic free-trade area. The idea is not new but there has been some buzz about it recently because the US and EU are both keen on developing the idea.

The most important consequence of a free-trade area would not be the abolition of tariffs. These are not very high to begin with. It is that it would allow products regulated in one jurisdiction to be traded freely elsewhere in the zone without further regulatory impediment.