Freed from the responsibility of being the first country to reject the treaty, pollsters now expect more than 60 per cent of Dutch voters to oppose it, compared with 54.87 per cent of French voters.

European governments had orchestrated referendums to encourage a “rolling yes” across Europe, but that now seems likely to backfire as a “rolling no” gathers pace instead.

Polls show that even voters in Luxembourg, due to hold a referendum on July 10, are growing increasingly wary of the treaty. EU diplomats had assumed that Luxembourg, where much of the tiny population works for European institutions, would deliver an overwhelming “yes”.

A Dutch “nee” vote would mean that two founding members of the Union have rejected the treaty, which diplomats agree will make it futile to try to resuscitate it. The British Government is waiting until after the Dutch vote to announce its referendum plans.

Even before the French vote, polls showed that the majority of Dutch opposed the treaty, but many still supported it because of government warnings of disaster if the Netherlands were the only country to reject it. Ministers claimed that isolation in Europe would be ruinous for the Dutch economy, and “yes” campaigners suggested that if the Dutch rejected the treaty they would be responsible for a return to war and genocide in Europe, playing TV adverts showing Jews being loaded on to trains during the Holocaust and a massacre in former Yugoslavia.

Harry van Bommel, a Socialist MP and leading “no” campaigner, said: “It has always been said in the Netherlands [that] we should not become Europe’s village idiot by voting ‘no’. This will give the Dutch more confidence to say ‘no’ to this constitution.”

As the referendum approached, “yes” voters in the Netherlands had been closing the gap but Maurice de Hond, the country’s leading pollster, said that this would now be reversed. “In the last week, the increase in the ‘yes’ vote is because people believed the government line that the Netherlands could not be the only one to vote ‘no ’,” he said. “They now have less reason to vote.”

With France already having broken ranks, the turnout is expected to be lower. Surveys suggest, however, that “no” voters are far more motivated that “yes” voters, so a low turnout will probably increase the margin of rejection.

After the French result, Jan Peter Balkenende, the Dutch Prime Minister, said that there was now even more reason to vote “yes”, to ensure that Europe got the constitution it needed.

Laurens Jan Brinkhorst, the Economy Minister, insisted that there was still everything to play for. “The outcome in the Netherlands can only be determined on the very last day since we are not a province of France, we are not a province of Europe, we are an independent country,” he said.

Dutch politicians are thought to feel relieved at the French result because it means that the Netherlands will not now be the first country to reject the constitution. Instead of being a Dutch political problem, the constitution has become a problem for all of Europe.

Michiel van Hulten, the leader of the “yes” campaign, said: “It will now take a small miracle for us to win on Wednesday. The ‘no’ voters have been legitimised by the French outcome.”

Is the constitution dead?

The European Commission insists that it is still very much alive, and that countries should push ahead and ratify it. Most leaders accept that it is dead, and will certainly be so if the Dutch, as expected, also reject it tomorrow.

Will the EU grind to a halt?

No. It will carry on working under the existing treaties. The crisis will, however, probably make decision-making more difficult and decrease the number of new laws.

Does it mean the end of 50 years of European integration?

France, which has been the motor of European integration, is now politically damaged, reducing its ability to push for “ever-closer union”. Many politicians in other countries insist that the crisis has arisen from too little integration, rather than too much.

What happens now?

EU leaders will meet on June 16 to work out what to do. They are expected to agree to shelve the constitution, but then decide what parts can be implemented without ratifying it.

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