From Brown to blue: Britain’s likely next prime minister David Cameron has been called a “pragmatic sceptic”. Photograph: Reuters

When will the real David Cameron stand up and tell us his position on Europe? If and when he becomes prime minister, but not before.

It is looking increasingly like “when” rather than “if”, and yet the policies of a Cameron government on Europe remain opaque, even to many of his own Conservative MPs.

This is not by accident. The Tory leader does not believe Europe stirs the passions of British voters. His top priority on taking office would be to sort out a messy economic inheritance. While the European issue can be largely sidelined now, he would not enjoy that luxury in Downing Street.

There are real fears in Brussels and European capitals that Cameron would head the most Eurosceptic British government since Margaret Thatcher, and that it could be even more hardline. Thatcher’s cabinet included several prominent pro-Europeans. If Cameron takes office, there would probably be only one – Kenneth Clarke, the shadow business secretary, and he has promised not to re-open old wounds.

Trepidation about an isolationist British government increased following Cameron’s landmark decision to pull Tory MEPs out of the mainstream centre-right European People’s Party after the June European elections. Many Tories (including Clarke) thought he would never actually do it. Hardline Eurosceptics are delighted and feel reassured. For now, they say, Cameron is “one of us”.

But is he? One Tory frontbencher describes Cameron as a “real Eurosceptic”, saying he was scarred when as a 27-year-old political adviser to the then Chancellor of the Exchequer Norman Lamont, Britain was humiliatingly forced out of the European Exchange Rate Mechanism in 1992. Cameron also voted for Iain Duncan Smith, a Maastricht Treaty rebel whom he described as a “good egg” – rather than Clarke – in the final round of the 2001 Tory leadership election.

And yet the truth may be more complicated. Lord Lamont has described his former aide as a “mild Eurosceptic” and that is nearer the mark. A close friend calls him a “pragmatic sceptic who would engage with Europe”, while one aide adds, “What you see with David is what you get. He said he would pull out of the EPP and he did. There is no hidden agenda on Europe.”

The issue remains a sensitive one in the Tory party and Cameron has not been averse to indulging in a little Eurosceptic rhet......