Barring a last-minute reprieve, French President Jacques Chirac faces a humiliating defeat over the European Union Constitution that would leave him badly wounded two years before the next presidential election.

In an agitated address to the nation from his presidential Elysee Palace on Thursday evening, Mr Chirac looked anxious and almost desperate as he made a final appeal to voters to back the new EU charter in tomorrow's referendum.

"Panic in the Elysee," screamed the headline on the front page of Le Parisien newspaper.

"At the moment we are in the biggest state of panic there could be," Christophe Barbier, deputy editor of L'Express magazine, said of the political mood in France.

Despite Mr Chirac's final plea for votes, opinion polls suggest voters will issue a crushing indictment of his and his government's performance tomorrow. His last hope remains the 20 per cent of voters who polls show are still undecided. His gamble on holding a referendum on the treaty rather than a safe parliamentary vote seems to have backfired, suggesting he misread the public mood - just as he did in 1997 when he dissolved Parliament and his ruling conservatives lost power.

Defeat would weaken Mr Chirac, 72, after 10 years as President and would not augur well for his chances of winning a third term, especially as his personal poll ratings have fallen. "He will obviously be quite badly weakened if there's a no vote. It's a question of to what extent would he be weakened? Whether it would make him into a lame duck - that's a tricky one," said Francois Heisbourg, a political analyst.

Mr Chirac has said he will not quit because the question voters are being asked is about the Constitution - not about him.

But many voters see the referendum as a last chance to show their discontent with him and his government before presidential and parliamentary elections due in 2007.

"It's hard to see how Chirac, beaten in the referendum, could be credible for another presidential term," said Mr Barbier.

Mr Chirac's likely response to a no vote would be to dismiss Prime Minister Jean-Pierre Raffarin and reshuffle the Cabinet. Mr Chirac hinted at change on Thursday by promising to give a "new impetus" to the government after tomorrow's vote.

Possible successors as prime minister include Interior Minister Dominique de Villepin, a Chirac ally, and Nicolas Sarkozy, the head of Mr Chirac's centre-right party although his relations with Mr Chirac are difficult.

Mr Chirac's disaster when he dissolved parliament during a crisis in 1997 suggests he is unlikely to follow the example of German Chancellor Gerhard Schroeder, who opted for a federal election after his party lost a state election last Sunday.

"It was a failure when he did it before so I don't think he would do it again," said Paul Bacot, a political scientist at the Institute of Political Studies in Lyon.

Major policy changes appear unlikely, with the priority being to bring down the unemployment rate from a five-year high of 10.2 per cent and carry out a promise to cut income tax by 30 per cent during Mr Chirac's five-year second term.

The government also hopes the country can achieve economic growth of between 2.0 and 2.5 per cent in 2005 although the Organisation for Economic Cooperation and Development this week predicted only 1.4 per cent growth this year.

"Whoever is Jacques Chirac's Prime Minister, whatever the form of the government, the president's priority in the coming months... will remain reducing unemployment," Mr Raffarin said in a television interview earlier this week.

Less obvious is who would gain in the presidential race if voters reject the Constitution. François Hollande, leader of the opposition Socialist Party and a possible presidential challenger, would also suffer a defeat if voters reject the Constitution. He has backed the charter and his party is divided over the Constitution.

Former Prime Minister Laurent Fabius has led the "No" camp in the Socialist Party and may have presidential ambitions.

"If the no vote wins, on the one hand Mr Fabius will win, but on the other he will have lost. He will be seen as the spokesman of a defeat. He will not be seen as a statesman by other people," said political analyst Philippe Moreau-Defarges.

One man who could stand to gain is Mr Sarkozy, a former finance and interior minister who has used the referendum campaign to underline his policy differences with Chirac even though they are both on the centre right.

However, Mr Sarkozy's apparent marital problems also mean he could have political problems - his wife is a close political adviser. Rejection of the EU Constitution could also signal France is not ready for his radical reform agenda, analysts say.