Driven forward by the former European Commission president Jacques Delors, the former French president Francois Mitterrand and the former German chancellor Helmut Kohl, the euro is a rare example of the triumph of political mind over matter.Its architects know there are dangers in linking currencies and in a “one-size-fits-all” interest rate policy and that stresses will inevitably arise.Since exchange rates were linked in January 1999, the value of the currency has plunged from $1.18 to less than 90 cents. But there have been big advantages already and the eurozone survived the economic fallout of 11 September in reasonable shape and with none of the devaluations of old.Now notes and coins are here, early evidence suggests this venture for Europe presents unparalleled opportunities. Even the German population, which was never consulted by referendum on the change, has been reconciled. When mini-kits of euro coins were made available to the public early in December they were snapped up with extraordinary speed. More than 150 million of them ­ with 4.2 billion coins ­ have been bought. So vast was the demand that in Germany, Portugal, Finland and Luxembourg banks were authorised to make up their own kits from bulk stocks.Political leaders expect this enthusiasm to translate into a new, more positive mood towards the EU.

Yesterday, euro launch celebrations began in Brussels under the slogan “the European Union in your hand” and Mr Prodi believes that the use of notes and coins will foster “a common identity”.The French President, Jacques Chirac, said in his televised New Year’s Eve message: “The euro is a victory for Europe. After a century of being torn apart, of wars and tribulations, our continent is finally affirming its identity and power in peace, unity and stability.”Other leaders underscored that message as they welcomed the new currency. The Greek Prime Minister, whose country, with Finland, was the first to convert to the euro, one hour ahead of the other states, declared: “This is a milestone in Greek history. Now we are part of united Europe.”The UN secretary general, Kofi Annan, hailed the “political act of unity and integration” brought about by the euro.But in Britain, the Deputy Prime Minister, John Prescott, said it was a “silly notion” that the British government should take a view on euro entry before determining whether its five economic tests had been met.All this comes at a crucial juncture for Europe.

While the power of the European Commission in Brussels has waned, the 15 member states are pushing ahead in important new areas, such as the decision to create an EU rapid reaction force of 60,000 men by 2003. In the wake of 11 September, European governments have embarked on a revolutionary change in judicial co-operation. Extradition proceedings are to be replaced by an EU-wide arrest warrant. Some joke that Osama bin Laden has done more for European unity than anyone since Mr Delors.In little more than two years’ time there may be a proto-European constitution after a new effort to rewrite the EU’s treaty in 2004. Since 1999, the EU has been beset by political crises including the mass resignation of the European Commission and referendum rebuffs in Denmark (over euro membership) and Ireland (over the Nice Treaty).