450 million people, 20 official languages: welcome to the enlarged European Union

Europe's leaders put the final seal on the reunification of a continent divided by the Cold War as the EU expanded to 25 nations, becoming the world's biggest free trade area.

Europe's leaders put the final seal on the reunification of a continent divided by the Cold War as the EU expanded to 25 nations, becoming the world's biggest free trade area.

Leaders of nations once under Moscow's iron grip will take their place as full members of the EU today, alongside their Western European counterparts, in a summit at Phoenix Park in Dublin. The enlarged EU will be one of 450 million people and 20 official languages, stretching across three time zones.

Today's accession of the 10 mainly former Communist states was celebrated with parties, concerts and spectacular fireworks displays across the continent. In central and Eastern Europe the EU's blue and yellow flag was hoisted in ceremonies to mark the final break with 50 years of Soviet rule.

In Warsaw, Lech Walesa, whose Solidarity movement toppled the country's Communist regime in 1989, said: "Poland's entrance into the European Union fulfils my dreams and lifetime work."

The EU's commissioner for enlargement, Günther Verheughen, added: "1 May will be a milestone in the history of Europe. It is an opportunity to heal the wounds of the past."

Of the 10 new countries, Latvia, Lithuania and Estonia were part of the USSR and a further five - Poland, the Czech Republic, Slovakia, Slovenia and Hungary - were Soviet satellites. Malta and the Greek-controlled half of Cyprus are also being admitted.

European integration began as an act of Franco-German reconciliation at the end of the Second World War, but the EU now faces an equally profound challenge as it tries to integrate its new members. The organisation, which began as a club of six, has expanded before, but never on such a scale. With the exception of Poland, all the additions are small and most are young democracies with immature political systems.

Economic growth is high but, apart from Slovenia, Cyprus and Malta, all are poor. Poland's unemployment is around 20 per cent; according to some projections it will take Lithuania 57 years to catch up with living standards in France.

The mood of the EU these countries join is neither confident nor generous. The existing 15 nations have even failed to agree the modest reforms outlined in the draft EU constitution. Even if the deal is agreed, its ratification will mean a tough fight in nations, including the United Kingdom which is holding a referendum.

Its economy in stagnation, Germany, which traditionally oiled the EU with dollops of cash, is making it clear its generosity is at a limit. Farmers from the new nations will have to wait 10 years to get the same level of subsidy as their Western European counterparts; East European workers could have a seven-year wait to work legally in Germany, France and most other Western states. And structural funds of the type that revitalised the Republic of Ireland will be thinner on the ground, with just €40bn (£27bn) available between now and 2006.

But there are several hopeful signs. Among the 10 that join today, unsavoury leaders, such as Slovakia's ultra-nationalist Vladimir Meciar, have been discarded by voters who knew that to elect him would reduce prospects of joining the EU. Problems, such as Austrian worries over the safety of the Czech Republic's Temelin nuclear power station or Hungary's attempt to promote its minorities abroad, are being talked about soberly in committees.

Even beyond the borders of today's new Europe, the EU's benign influence is calming ethnic tensions in Macedonia and Bosnia Herzegovina as the lure of membership forces governments to behave responsibly.