One reason for Mr. Cameron’s 27-day turn-around on his clear and unambiguous promise to hold a referendum if he becomes Prime Minister “on any EU treaty that emerges from these negotiations” appears as the detail of yesterday’s press conference is disentangled from soundbite and spin. And it is the urge for power which has won out over principle.

Given the need to recover as many as possible of the fifty odd seats that have gone Liberal ‘Democrat’ since the years of Margaret Thatcher, Mr. Cameron has decided that lapsed conservatives and wobbly Lib ‘Dems’ must now be wooed into the tent. And if that means that the independence of the United Kingdom has to be sacrificed in exchange, so be it.

Thus he told questioners:

“If you are a Lib Dem voter … then there is a liberal Conservative party there for you.”

As your average Lib ‘Dem’ is also a Europhile, then there has to be a limit to this awkward business of having a referendum on the Constitution. Given that the ball game changes entirely if the Treaty comes into force, as it is likely to do if the next most likely date for a General Election is May or June 2009, promising a referendum on the treaty after it comes into force is plainly a promise too far for Mr. Cameron.

If the Constitutional Treaty is abhorrent now, such that the Conservative Party is committed not just to holding a Referendum upon it but will campaign strongly against ratification, why, pray does it cease to be abhorrent after it comes into force?