Labour and the Tories have more in common than they care to admit. But on Europe, the choice is clear – and historic

The contours of the political landscape have not been this sharply defined for two decades. With the general election a fixed date now little more than one year away, it feels as if the choice facing the British people is coming into focus.

There are a few preliminaries, of course. The local elections in many parts of England and Northern Ireland, and the European Parliament elections on the same day, 22 May, will provide a misleading preview. Indeed, in the case of the European elections, the preview may be more misleading than usual.

Psephologists have noted that the results of European elections have become more divergent from those of the following general elections. Thus, even if Nigel Farage’s occasionally xenophobic army wins the greatest share of the vote next month, this does not necessarily mean that it will succeed in electing even a single MP – not even the charismatic Mr Farage himself – next year.

Unfortunately, the European elections are the purest form of protest vote available under the British constitution, the equivalent of a national mid-term by-election. Many people will vote for the UK Independence Party not because they think it has the best policies for the European Parliament, an increasingly powerful institution of which Ukip believes we should have no part. They may not even vote Ukip because they want to leave the EU: the overwhelming motive is likely to be to express dissatisfaction with politics as usual. Equally, many people will vote Labour simply to register their unhappiness with the record of the Coalition Government over the past four years.

In the general election next year, however, the choice will be different – and the only respect in which the European elections offer a preview is that the question of Europe will be more important than is usual in elections for the House of Commons. Indeed, it is possible that Europe will be more important than in any general election since 1983, when Labour promised to withdraw from what was then called the EEC.

Next year’s election will offer a choice of prime ministers: David Cameron, who promises a referendum on our membership of the EU by the end of 2017, and Ed Miliband, who does not. This newspaper is not opposed to a referendum in principle. The EU has a problem of democratic legitimacy: the Brussels-Strasbourg Parliament is an unsatisfactory assembly, which is one reason why next month’s elections may be treated so frivolously, and the consent of the people of this country for the way the EU has changed since 1975 has not been tested. But 2017 is not the right time, and Mr Cameron has raised expectations of a renegotiation of the terms of our membership that he cannot possibly deliver. Most other member states have no wish to rewrite treaties, which would in any case take longer than the deadline Mr Cameron has set.

The next general election will be about more than our relationship with the rest of Europe, of course. And there is another important preliminary in the Scottish referendum in September, which will decide the boundaries of the nation that Mr Cameron and Mr Miliband will be competing to govern. But, despite Mr Miliband’s sometimes extravagant anti-capitalist rhetoric, there is perhaps less difference between the two main parties on the economy than either of them pretends.

However, because of Mr Cameron’s promise of an EU referendum, the choice we face in a year’s time will be, in one respect at least, a potentially momentous one.