By ANDREW DUFFLiberal DemocratAFTER 18 months solid work, the European Convention closed its doors for the last time on Thursday. Along with the huge majority of its members, I signed the draft constitution, shook hands with our president Valéry Giscard d'Estaing, and went off to lunch.

AFTER 18 months solid work, the European Convention closed its doors for the last time on Thursday. Along with the huge majority of its members, I signed the draft constitution, shook hands with our president Valéry Giscard d'Estaing, and went off to lunch.

The Convention was a radical departure from the way things are normally done in Europe. It was large, pluralistic and open, combining in its working methods the best of both parliamentary and diplomatic styles. By forcing governments to justify their positions in public, the Convention was refreshingly subversive.

The Union's values and objectives, clearly set out in the draft Constitution, are liberal, democratic and progressive. The Constitution – which can be found in full on the Internet at http://european-convention.eu.int – has clarified who does what in Europe. It strengthens the capacity of the Union to act effectively at home and abroad. European citizenship takes a leap forward, protected by the Charter of Fundamental Rights, which will be binding. The untidy jumble of instruments and decision-making procedures has been streamlined.

The Council of Ministers will take more decisions by qualified majority voting (QMV), and the Parliament's law making and budgetary powers have been multiplied. Had it not been for the UK government, there would have been yet more QMV in foreign, fiscal and social policy.

Indeed, the UK government, already marginalised because it invaded Iraq, made few new friends in the Convention. It appeared leaderless and was not trusted. The British Tories, meanwhile, joined with some Moscow trained anti-Europeans to oppose the consensus.

The outcome of the Convention will certainly be a big issue in next year's election campaign for the European Parliament. Many, both pro and anti-Constitution, want a referendum to be held at the same time. The referendum argument is superficially attractive, especially when set against Mr Blair's dismal cop-out on the euro. But beware. If a British referendum were to fail to endorse the new constitution the reform package would be blocked not just for Britain but for all Europe.

Were the government to accept that the UK does not have a moral or political right to block the constitutional progress for the rest of Europe, a referendum would be an option. But the risks are very great. If our partners chose to ratify the Constitution, Britain would have no choice, in the event of a No vote, but to seek a second-class membership of a Union that had been refounded on a constitutional, federal basis. Not an attractive prospect. No euro, no Constitution, no say in the great decisions which will shape our continent in the 21st century.

Andrew Duff, MEP for the East of England, led the European Liberal Democrat group at the Convention and was Vice-President of the European Parliament's Convention delegation. www.andrewduffmep.org.