You gotta dance with the one that brung ya. Ronald Reagan’s aphorism, taken from a 1920s country song, expresses a general truth about politics. On the way to victory you acquire allies and incur obligations, and when you get there, you cannot ignore them.

Politicians, like the heroine of Erica Jong’s Fear of Flying, might dream of consummation without commitment. Like her, they may see it as “the purest thing there is”. But like her, they’re doomed to discover that such a relationship “is rarer than the unicorn. And I have never had one.”

It’s because you gotta dance with the one that brung ya that we are having this referendum in the first place. David Cameron was not free to ignore the demands