Tony Blair gave a passionate speech last night in support of the new, enlarged European Union.

Speaking at a launch party to welcome the ten accession states, the Prime Minister described the occasion as an "historic moment of opportunity, change and progress for these countries".

The ten countries - the Czech Republic, Poland, Estonia, Latvia, Lithuania, Slovakia, Hungary, Cyprus, Slovenia and Malta - are due to become part of the union on Saturday, denoting the end of years of European division.

Mr Blair said the new Europe was the result of fighting off the "forces of darkness" of the past.

He said: "These are countries whose desire for freedom and independence is measured in the blood and sacrifice of countless millions of people."

He insisted those states within an enlarged Europe would not lose their identity.

"The countries coming into the European Union are not countries who want to sacrifice their nationhood or independence," he said.

"This is a moment to reflect on the idealism that created the European Union. We should indeed celebrate May 1, whatever the difficulties."

Mr Blair said that it was time the ten states took their rightful place in Europe, and insisted: "We will be your allies."

Earlier, Downing Street rejected suggestions of a rift with France over Mr Blair's decision to call a referendum on the EU constitution.

The Prime Minister defended the move in an article for a French newspaper, which was seen as adding to the pressure on President Jacques Chirac, who has been resisting calls to hold a referendum on the issue.

Mr Blair's spokesman said that the article was predominantly about EU enlargement and only one paragraph referred to the referendum decision.

He said Mr Blair had previously discussed his decision to hold a referendum with the French president during a telephone conversations.

"President Chirac perfectly understood why the Prime Minister took the decision that he did," he said.

* There will be no mass influx of students from states joining the EU next month, the Government says.

When top-up fees are introduced in 2006, EU students will be allowed to pay nothing until after they graduate, with the British taxpayer footing the bill in the meantime.

Under the new fees regime, the Government will pay universities and then collect the charge from graduates once they are earning more than £15,000 a year.

Critics have warned that it will be difficult to collect the money from graduates from elsewhere in the EU once they return to their native countries.

But a spokesman for the Department for Education and Skills said:"Studying in our universities is not a cheap option for EU students and we are not expecting a mass influx."