IT was a spring evening nearly three years ago. In the run-up to the last election, the then-leader of the opposition pitched up at Holmfirth High School for one of his last Cameron Direct speaking events.

This humble columnist was among the crowd of 150 in the hall as the Conservative leader fielded questions from an invited audience, only some of whom were paid-up party members.

Typically for David Cameron in his pre-Prime Minister days, he tried to be all things to all men while gently pushing the idea that the country would be a better place if the electorate were good enough to give him the keys to Number 10.

But amid the platitudes, there were two moments when the Conservative leader challenged the world view of people who may well have been Tory voters.

A female questioner demanded to know when Scottish MPs would be “disbarred” from the House of Commons during English-only business.

While accepting there was a problem, Mr Cameron refused to pander to the to-Hell-with-the-Jocks mentality which has gained a lot of ground in the last decade.

“I love the UK,” he told the Holmfirth audience. “We’re a family. I’d rather have an imperfect union than a perfect divorce.”

Three years on, as the independence referendum looms, it’s fair to say this is still Mr Cameron’s position – that the UK is better together, whatever the anomalies of devolution.

But on that other union – the one with a blue and yellow flag – the Conservative leader has been less consistent.

“Will we have a referendum on membership of the European Union?” enquired an audience member in Holmfirth three years ago.

“I don’t think we should have a referendum on membership,” Mr Cameron replied. “I think we have to be a member because we’re a trading nation. We mustn’t cut ourselves off from those markets.”

Cameron Version 2010 refused to play to the gallery by denouncing Brussels and all its works.

Instead he told the audience what some of them didn’t want to hear – that Britain was better in than out.

In two days’ time the Prime Minister will give a major speech in the Netherlands in which he is due to spell out again why the UK should stay in the EU. You can expect him to use similar language in Holland as he did in Holmfirth, explaining the economic benefits of membership of such a large trading bloc.

But this time, unlike in the Holme Valley three years ago, Mr Cameron is expected to say that Britain should have a referendum on whether to stay in the EU.

So what’s changed since 2010? Well, a cynic would answer with four letters: U, K, I and P. The anti-EU party is now consistently polling in double figures, easily enough to deny the Conservatives victory in the next general election.

The promise of a referendum could be no more than a ploy to win back disillusioned Tories who have drifted towards Nigel Farage and chums in the last few years.

A more charitable explanation is that Mr Cameron’s referendum U-turn is no more than common sense. “When the facts change, I change my mind,” as John Maynard Keynes never said.

Back in March 2010, when the Tory leader was telling the people of the Holme Valley that a referendum was a bad idea, the full extent of the euro crisis was not yet clear.

Three years on it is obvious that saving the single currency will involve deepening the bonds between the 17 countries who are members – and changing their relationship with the other 10, including Britain, who are not.

Perhaps this rebooted EU needs a fresh endorsement at the ballot box.

Perhaps Mr Cameron will campaign for Britain to remain in the union, despite the difficulties.

And perhaps those who have loudly demanded a referendum on EU membership will find out that they may be vocal but they are also a minority.