Unanimity

Unanimity is the form of decision-making used by the Council of Ministers on sensitive issues such as tax or social security.

Unlike the council's other decision process - qualified majority voting - unanimity means the entire council must agree on a proposal to pass it. Any single member state can use its veto to reject a proposal.

In decisions taken by unanimity, the European Parliament has no deciding power and can only offer its opinion to the council.

As the EU enlarges to take in another 12 members, there is increasing pressure to increase the number of issues which are decided on by qualified majority voting.

Unanimity can make negotiations very long and complex and the disagreement of one country can scupper a whole agreement.

But national governments are keen to keep their right of veto on issues which are especially sensitive.

At the 2000 Nice summit unanimity was an important and difficult part of the negotiations.

In the end, QMV was extended to trade and some immigration, visa and asylum issues. As of 2007 it will also apply to structural funds - the EU's support money for the less well-off regions of the EU.

But after hours of wrangling unanimity was maintained on taxation and on social security.