PRESIDENT CHIRAC embarks on a make-or-break attempt tomorrow to persuade voters to approve the European Union constitution after a poll yesterday showed the “no” majority increasing before the French referendum on May 29.

His mission is to break the momentum of a cross-party tide of protest that includes a majority of left-wing voters, the nationalist Right and a third of his own centre-right coalition. In a reflection of the sorry state of the “yes” campaign, commentators say that M Chirac must provide one simple and positive argument for saying “oui”.

He will face that challenge in a debate with 80 young adults in an evening appearance at the Elysée Palace on TF1 television, the most popular channel. The “yes” campaign has so far had little success brandishing the spectre of disaster in the event of a “non”.

M Chirac’s main target will be the left-wing voters — his political opponents — who have turned massively against the treaty in the belief that it amounts to a British-led plot to destroy France’s protective social system. The President will argue that, on the contrary, the Constitution will shore up “the European social model that is founded on justice and solidarity”, his aides said.

The President’s choice of a tame television format, stage-managed by Claude Chirac, his daughter and media manager, has caused a row. The “no” camp is accusing him of cowardice for refusing debate with politicians and using chat-show hosts to mediate rather than political interviewers. In 1992 the late President Mitterrand, a Socialist, turned the tide and saved the Maastricht treaty with a robust debate against the leader of the conservative “no” campaign just before that year’s referendum.

On the constitution, the rejectionist camp has so far made the running against a stumbling campaign by Jean-Pierre Raffarin, the Prime Minister, and the leadership of the opposition Socialist Party, to convince voters that a “non” would be self-destructive folly. The latest poll, by Ipsos for Le Figaro, showed the “no” majority rising by one point to 53 per cent in a week. Polls, deemed more accurate than in election campaigns, have placed the “no” at 52-54 per cent for the past three weeks after a winter in which the “yes” camp enjoyed around 60 per cent support.

With defeat looming for the Establishment, the campaign has turned brutal. François Hollande, the Socialist leader, whose job and presidential hopes are at stake, is accusing dissenting colleagues of playing the game of Jean-Marie Le Pen, chief of the far-right National Front, who opposes all EU treaties. A gleeful M Le Pen is predicting a repeat of the anti-Establishment upset in April 2002, when the defection of Socialist voters from Lionel Jospin, their candidate, let him break into the run-off in the presidential election against M Chirac.

The knives are out in the Chirac camp, with the President’s allies accusing Nicolas Sarkozy, leader of his Union for a Popular Majority party, of deliberate lacklustre campaigning because a “no” would further his own ambition to replace M Chirac. The political heirs of the late General Charles de Gaulle are also feuding over which way their hero would have voted.

The good news in yesterday’s poll for M Chirac was that 40 per cent of those planning to vote were not fully decided or refused to give an opinion. However, Pierre Giacometti, director of the Ipsos institute, said that commitment to a “no” was taking root.

“This is no longer a ‘no’ from bad temper. It is a ‘no’ from conviction,” he said.

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