David Cameron has always presented himself as a “pretty straightforward sort of person” in the Tony Blair mould of the mid-1990s. Now, he needs to deploy the more devious political skills of the two Harolds of the 1960s — Macmillan and Wilson — in trying to reconcile incompatible objectives.

Mr Cameron’s primary aim is to prevent a confrontation with the European Union from dominating his first two years as Prime Minister, when he will be preoccupied with sorting out Britain’s acute fiscal problems. While British voters are pretty Eurosceptic, Europe is a very low priority for most.

Yet the Tories have strongly opposed the Lisbon treaty and demanded a referendum. Abandoning that pledge was inevitable once the Czechs ratified. Any other course would have risked what would have become an in/out referendum, the very choice which Mr Cameron most wants to avoid.

The fallback position of “not letting matters rest” is full of dangers. If plan B, due this afternoon, is insufficiently robust, his own troops will cry “betrayal” — as hardline sceptics have already done. This offers an opening which Nigel Farage of the UK Independence Party has been awaiting with relish.

But the rest of the EU is not about to roll over and agree to a repatriation of powers from Brussels to London since this would reopen, and unravel, all the institutional compromises which they hoped to have closed yesterday. The most that other EU countries may concede is symbolic reassurances of the kind that satisfied Ireland and the Czech Republic. That will not be nearly enough for Tory sceptics, and some in the Shadow Cabinet.

Harold Wilson’s renegotiation of the British terms in 1974 produced largely empty changes. But the referendum in 1975 reaffirmed membership by a two to one margin because all three main parties agreed. The Tories have talked of making future EU treaties subject to a referendum. But does that include accession treaties like the possible one on Croatia which will include the reassurances made to Ireland and the Czechs? Does Mr Cameron want to get involved in a referendum at a time when his Government may be very unpopular over spending cuts?

The balance between substance (the sceptic demand) and symbolism (the EU limit) will require adept political footwork. But, as he has shown over the expenses row, Mr Cameron has always been willing to be ruthless in the pursuit of power.

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