ANDREW DUFF: EU AT 50

12.41.07pm GMT Fri 23rd Mar 2007

50th birthday parties, believe me, can be quite fun. Because Germany holds the current presidency of the Council of the European Union, Berlin is the focus of the celebration of the signing of the Treaty of Rome, establishing the European Economic Community in 1957. Liberal Democrats should recall that among the first British politicians to welcome the setting up of the EEC were Jo Grimond and Mark Bonham Carter. On the Labour benches, the ranks of the Gaitskellites were split open by the evidence that the economic integration of the six original EEC countries was proving a success. Many Tories, led by Harold Macmillan, were soon converted to the European cause. But it was the Liberals who led the way.

While the official positions of Labour and the Conservatives flip-flopped over Europe, the Liberals remained steadfast. It was Jeremy Thorpe's European vocation in 1974 that led me then to join the party. In 1975, when I was working for the magnificent pro-European Labour MP John Mackintosh, all the pro-Europeans met up to fight and win the referendum campaign on staying in the EEC. George Thomson and then Roy Jenkins became European Commissioners, and, later, they and most of the other 69 Labour MPs who had backed UK accession to the European Community crossed the floor to form the SDP. In 1992-93 it was Paddy Ashdown's trenchant leadership in the Commons which saved the Treaty of Maastricht from certain defeat by the Labour Opposition and Tory rebels. Had Maastricht gone down in Britain, it would have gone down everywhere. One way or the other, the success of our movement is bound up with that of the European Union.

So Lib Dems have much to celebrate this weekend. But it should not just be a self-congratulatory party. The Berlin Declaration, carefully crafted, quite rightly pays tribute to the work of the founding fathers. It also speaks of the liberal values which informed the birth of the EU and of the processes of democracy, human rights and the rule of law by which unification has developed. The Declaration notes the remarkable successes of European integration - the customs union, the social market economy, competition policy, the single market, the euro, the independent Central Bank, the free movement of people within a common area of security and justice, and, not least, enlargement to the East. It notes, too, the challenges of globalisation, notably energy, climate change and international insecurity, before closing with a springboard to the next big decision of the European Union, scheduled for June, about how to salvage the constitutional treaty.

Many will be tempted to take all this commemoration for granted, as if there is an historic inevitability about European unity. That would be a mistake. Although magnificent in its achievements, the European Union is still strangely experimental. There were - and are - setbacks. The forces of illiberalism, although tamed, are never vanquished. In the Balkans and in Cyprus, and even in Ulster, the charm of European integration has yet to fulfil its potential. The European Union has still to discover the powerful instruments it needs if it is to project its own advances in terms of peace, prosperity and security on to the world stage. At home, public opinion is disorientated by the scale and pace of integration, and political leaders are too often tongue-tied and weak-kneed when they ought to be extending their reach into the European dimension.

The work of European liberals is far from done. If there is ever to be a constitutional settlement of the Union, the economic governance of the EU must be strengthened. We need better architecture for the organisation of economic society. The fight against climate change should be up-graded, allowing for radical reform of the EU's common energy, agriculture and fisheries policies. We should spell out policy on future enlargement. And we should aim for a reformed financial system which is fair and buoyant, ensuring that the Union's spending matches directly its modern political priorities.

Fortunately, all of that - an improved 'Constitution Plus' rather than an impoverished mini-Treaty - is within the grasp of the German presidency. As we party in Berlin this weekend, this should be our more sober preoccupation.

Andrew Duff leads the UK Liberal Democrats in the European Parliament.