European Elections: Explaining the mysterious British veto: John Lichfield writes the first of a series examining issues thrown up by the European parliament campaign

Is there such a thing as 'the British veto'?

It depends what you mean by veto. You could argue we have three different kinds; on the other hand, you could argue we have none.

Come again?

There are several ways in which Britain can block developments which it dislikes. In practice, however, the European Union - like Canada, the Major cabinet and most marriages - is a state of permanent negotiation. The veto is an instrument which can break in your hand (as the Government found in the recent row over voting rights in the enlarged EU).

But what kind of vetoes do we have?

Day-to-day policy decisions in the EU are taken by member governments sitting in the Council of Ministers. Decisions in most areas are supposed to be taken by 'qualified' majority vote; in other words Britain can be outvoted unless it assembles a big enough minority of like-minded allies to block a decision. The Single European Act and Maastricht treaty (the first agreed by Baroness Thatcher; the second by John Major) expanded the areas in which majority votes can be taken and thus weakened the British veto. However, decisions in a few areas still have to be taken unanimously: all 12 countries have to agree; thus all 12 have a veto. The areas include foreign affairs, taxation and justice.

That's one kind of veto. What about the other two?

Any constitutional changes to the EU treaties - to make the EU more federal, or (Euro-sceptics note) less federal - have to be agreed by all 12 members. Thus Britain has a formal veto over constitutional change.

The third kind of veto, the Luxembourg Compromise, does not legally exist; it's a gentleman's agreement between members (disputed by some) that one country can indefinitely block a majority vote in the Council of Ministers if it believes that its 'very important interests' are threatened.

Has Britain ever used any of these vetoes?

Britain has only once invoked the Luxembourg Compromise - over farm prices in May 1982 - and failed to make it stick. It has sometimes used, or at least threatened, its more formal veto rights. But vetoes are a little like nuclear weapons: they rarely have to be used but they do shape the frontiers of the negotiation.

The existence of veto rights, of one kind or another, helps Britain to get its way, or something close to its way, in Brussels. But ultimately the EU is about deal- making. Even the constitutional veto has its limits; the other member states can by- pass Britain as they did by agreeing separately the Social Chapter of the Maastricht treaty or setting up the exchange rate mechanism of the EMS.

Is the 'veto' under threat?

The European Commission and some member states would like to see even more majority voting in the Council of Ministers, in areas such as foreign policy and taxation. There is no formal attempt to abolish the constitutional veto or Luxembourg Compromise.

Does Labour want to abandon the British veto, as the Tories claim?

No. The European Socialist manifesto calls for more majority voting. Labour signed it but it was agreed that national parties could disagree on specific points. Labour's own European election manifesto calls for the veto (that is, unanimous voting in the Council of Ministers) to be maintained over foreign affairs, security and fiscal issues. The Liberal Democrats are more open to changes in the voting system.

Should we lie awake at nights worrying about the British veto?

No. Mostly, this is a red, white and blue herring. The British politician who has done the most to 'weaken' the British veto in the EU is Lady Thatcher, when she signed the Single European Act.