David Cameron has been deliberately vague about his plans as Tory leader. But he has made one clear commitment: to pull Conservative MEPs out of the European People’s Party (EPP), the self-described “mainstream Centre and Centre-Right” group of the European Parliament.

The received wisdom is that it is not just his first commitment; it is also his first mistake. According, for instance, to the commentator Andrew Rawnsley, the pledge is simply a bone Mr Cameron has thrown to the right of his party — “a step too Europhobic even for Iain Duncan Smith”.

It never takes long for the accusation of Europhobia to emerge when someone dares to question mushy bien pensant opinion over Europe.

But there is a rule of thumb when dealing with EU issues: that whatever the ranks of the commentariat recommend, the opposite is almost always the most sensible course of action. Opponents of ERM membership were, for example, depicted as Europhobic cranks. Once the Government had done as the chattering classes demanded and joined, it soon became clear who were the real cranks.

Far from being a mistake, and still less Europhobic, Mr Cameron’s pledge is both principled and politically sensible. The Conservative Party now has a settled position on Europe, at one with mainstream public opinion — in Europe but not run by Europe, as William Hague put it.

The EPP also has a settled position: in favour of a European army and police force, the single currency, tax-raising powers for MEPs and a single EU seat at the UN. It remains determined that the EU constitution be adopted as it stands.

The mistake is not pulling out of such a group, it is to even consider remaining in it. As Lance Price reveals in his diary as a Downing Street spin-doctor, Tony Blair was wise to this, and planned to use the party’s membership of the EPP as a weapon in any referendum on the single currency.

Instead of remaining in an abusive arranged marriage, Mr Cameron is right to seek a divorce, and to build a new marriage with MEPs from other countries who believe in self-government rather than ever increasing powers for the EU. If for no other reason than that the wiseacres tell him not to.