David Cameron would not campaign for a “No” vote if the British people were asked in a referendum if they wanted to stay in the European Union. That is one of the main news items to come out of a wide-ranging interview the PM has given to the Daily Telegraph at the start of the long summer recess.

At one level, it isn’t that much of a surprise. In a long parliamentary debate after the last European Council summit, Cameron expressed, albeit in fairly delicate terms, the very same point. He indicated that he doesn’t want to hold a referendum now, because the nature of the EU is changing rapidly in response to the single currency crisis. He would rather wait to see what institutional adjustments and treaty changes emerge, use those amendments to negotiate a different, looser relationship with Brussels and then perhaps consult the nation on whether his preferred EU terms are acceptable.

It stands to reason that he expects his negotiations to be successful, or at least that he would only dare hold a referendum if he thought he had wangled a decent package, including “repatriation” of powers. So, by extension, he would be selling a deal with his name on it. Naturally he would then campaign for a “yes” vote.

The curious thing is that he has chosen to spell it out again now in black and white. Anyone familiar with or who cares about the way EU diplomacy actually works knows it would be an affront for an incumbent British PM to go around advertising in advance that he might campaign for complete exit. And those who think exit is the only serious and desirable option already suspect Cameron of being a bit of a Brussels quisling. So the only thing this interview line can achieve is rubbing the sceptics’ noses in the fact that they don’t have a friend in Number 10. An odd choice, given the difficulties Cameron already has with party management.

But the real problem Cameron has with all this stuff is the complacency (or naivete?) in thinking he will get a renegotiation deal that will satisfy the Tories. The argument usually deployed is that Britain is a desirable market for our European neighbours and a purchaser of their goods and services. Ergo, they will want to keep us on side and will acquiesce to our demands.

There are two problems. First, diplomacy can trump economics in Europe. Cameron has persistently underestimated how fed up the rest of the continent is with the UK’s half-hearted engagement – the in/out “hokey-cokey” approach. This goes back way further than the current government. The Germans in particular are said to be impatient and their appetite to meet London’s needs is diminished further by conspicuous Schadenfreude among Tories over the failings in the single currency project. The British message in Brussels at the moment boils down to: “We’re sorry that you’ve made a right hash of everything. We did warn you. It’s not really our problem, except when it impacts on our growth. So could you please sort it out. Follow policies of deeper integration, which we despise and would never pursue ourselves and then, when you’ve finished, could we please have a whole bunch of social policies back plus other yet-to-be named dispensations? Oh, and by the way, we’ll veto your treaties unless you give us what we want. And did we add that we won’t surrender any control over the terms of the single market. We must stay at the top table at all times. Is that ok?”

A Whitehall source, who has discussed these things with senior figures in Angela Merkel’s office, recently ran this proposition past German counterparts and reports that: “The answer is ‘no’”. Of course it is.
 
Second, even if Cameron negotiates some nominal repatriation of powers – a looser arrangement on paper – and even if he secures formal guarantees that our status in the single market is preserved, he can’t deliver that protection in practice. He can do nothing about “caucusing”. This is the process by which members of a new, ultra-integrated, consolidated Eurozone turn up at wider EU summits with pre-agreed positions that can be voted through, whether Britain likes it or not. In other words, Cameron could have a piece of paper saying the UK will not be disadvantaged in the single market and wave it around like crazy when he steps off the Eurostar, but it won’t matter because we’ll be marginalised when it comes to the detail of all subsequent rule changes. The sceptics understand this perfectly well and so won’t be fooled by any “renegotiation”. They will still want out.

So really Cameron’s message is that he can’t give his party what it really wants on Europe and he won’t pretend that he can. That is a brave line to take given the current mood of the Conservative benches.

PS. For further reading on UK relations with the EU, by far the best thing published recently is this excellent Centre for European Reform pamphlet by David Rennie of the Economist.