With 99.8% of ballots counted, unofficial results showed 61.6% had voted no to the constitution, with 38.4% saying yes. The level of opposition, and the turnout of 62.8%, exceeded all projections.

The Dutch revolt against their rulers in The Hague and Brussels is without parallel. For 50 years, the Netherlands has been a stronghold of European integration and the home to the Maastricht treaty that produced the euro single currency - the most striking instrument of unification.

Until the final hours of voting, the Dutch government campaigned for the charter, and the extent of opposition was a body blow.

Jan Peter Balkenende, the prime minister, swiftly conceded defeat and acknowledged the gap between politicians and the electorate. "The idea of Europe has lived for the politicians, but not the Dutch people," he said. "That will have to change."

The French president, Jacques Chirac, said the Dutch vote - which came just three days after France rejected the EU constitution - had exposed "questions and concerns about the development of the European project".

In Germany, the chancellor, Gerhard Schröder, said the situation "must not become Europe's general crisis".

Dutch newspaper headlines today were as stark as the outcome of the Dutch vote. "Devastating no," the mass circulation Algemeen Dagblad said.

The Volkskrant daily called the outcome "the reckoning of the common man", adding: "The Dutch were always at the forefront of European Union, but now the good kid in the class is the scene of an anti-European rebellion."

Opponents of the EU constitution described the result as a breakthrough for European democracy. Harry van Bommel, who led the no campaign for the Socialist party, was cheered by celebrating crowds in Amsterdam and said: "It's the people - who for 50 years had to keep quiet about the direction, structure and future of Europe - who won tonight."

Geert Wilders, a rightwing member of parliament with strong views on immigration, said he was "incredibly happy that the Dutch voter has rubbed it in the faces of the political elite in The Hague and Brussels".

Although nine of the 25 EU member states have already ratified the treaty, European leaders last night appeared to be closer to an acceptance that the two referendum results had killed off the constitution.

Speaking at a late-night press conference, the European commission president, Jose Manuel Barroso, made no mention of the need to continue with ratification. "It is a difficult moment for Europe," he said, adding that heads of government would decide what to do next at their summit in two weeks.

However, he warned EU leaders not to abandon the treaty yet, saying: "I think it will not be wise [for] leaders to come with new initiatives or unilateral decisions."

In Britain politicians were sanguine, but reluctant to admit defeat. The foreign secretary, Jack Straw, said the verdict of French and Dutch voters "raises profound questions for all of us about the future direction of Europe".

Europe minister Douglas Alexander acknowledged that the French and Dutch results had left the constitutional treaty in "serious difficulty", but insisted that "this treaty was agreed by 25 nations ... it is not for one country to declare it dead".

The prime minister, Tony Blair, was confident fellow European leaders would accept it was impossible to carry on in the wake of such an emphatic dual rejection. However, he acknowledged that it could take time for Mr Chirac to concede the constitution was dead.

Elsewhere, politicians were less circumspect. In Italy, the deputy prime minister, Giulio Tremonti, said the current constitution was "finished".

Anti-Muslim sentiment, opposition to EU membership for Turkey and fears over losing control of immigration policy all contributed to the French and Dutch votes.

In the Netherlands, the no camp was helped by a weak government yes campaign which began late and appeared to take the electorate for granted.

As the biggest per capita contributors to the Brussels budget, the Dutch feel bullied by bigger countries and let down by the single currency, which is seen as having brought steep price rises. The Netherlands economy is stagnant, and unemployment has risen to 7%.

For Europe as a whole, the coming weeks and months - coinciding with the British assumption of the EU presidency - seem likely to produce bitter clashes on everything from Turkish accession and enlargement to budget agreements and economic policy.

There is also the question of what can be salvaged from the EU constitution, which took two years to be agreed.

Yesterday, Latvia's parliament voted by a large majority to support the legislation, a decision it said sent a message from the new Europe to the old that the approval process must continue.

· Where the ratification process stands

Rejected:

France: referendum, May 29 2005

Netherlands: referendum, June 1 2005

Ratified: Lithuania: parliament, November 11 2004

Hungary: parliament, December 20 2004

Slovenia: parliament, February 1 2005

Spain: referendum, February 20 2005

Italy: parliament, April 6 2005

Greece: parliament, April 19 2005

Slovakia: parliament, May 11 2005

Austria: parliament, May 25 2005

Germany: parliament, May 12 and 27 2005

Latvia: parliament, June 1 2005

Yet to decide:

Luxembourg: referendum, July 10 2005

Denmark: referendum, September 27 2005

Portugal: referendum, December 2005

Belgium: parliament, June 2005

Estonia: parliament, June 2005

Cyprus: parliament, June 2005

Malta: parliament, July 2005

Finland: parliament, Autumn 2005

Sweden: parliament, December 2005

Czech Republic: referendum, mid-2006

Britain: referendum, no date set

Ireland: referendum, no date set

Poland: undecided