President Nicolas Sarkozy's chances of holding on to power were fading two days before France's election runoff, with far-right and centrist leaders refusing to endorse him and his usually bland Socialist rival performing confidently in a TV debate.

The last opinion polls published on Friday before Sunday's vote suggested that Socialist challenger Francois Hollande's lead has narrowed to as little as five percentage points from as much as 10 in the last few days as the race has tightened.

However, centrist Francois Bayrou buried one of Sarkozy's last hopes of catching up when he announced he would vote for Hollande on Sunday and left his supporters free to make up their own minds.

Bayrou, who came fifth in the first round with 9 percent, attacked Sarkozy's tough talk on immigration and Europe, aimed at winning over the nearly one in five voters who picked far-right leader Marine Le Pen in round one. The anti-immigration National Front leader also snubbed Sarkozy this week saying she would cast a blank vote on Sunday.

A bitter Sarkozy retorted on Friday that Bayrou 'indicated that having thought about it carefully, he would vote for Francois Hollande and went on to say 'who would lead the country to bankruptcy in February'.'

Opinion polls conducted since Wednesday evening's television debate found Sarkozy making up ground against Hollande. However, the challenger's reduced advance would be tough to overcome so close to the vote.

Two polls by Ipsos and BVA found Hollande's lead had narrowed by one percentage point, with 52.5 percent of voting intentions to Sarkozy's 47.5 percent.

Surveys by CSA and Harris Interactive showed Hollande's lead shrinking from eight points to six after the debate, with 53 percent support to Sarkozy's 47 percent.

TNS-Sofres showed Hollande's score edging down 1.5 points to 53.5 percent from last week, with Sarkozy rising to 46.5 percent from 45 percent previously.

Overconfidence

Despite his lead, Hollande said he could not totally rule out the possibility of defeat because the participation rate, transfer votes from eliminated candidates and blank votes would be key. Moreover, he said that he never underestimated Sarkozy.

'Where he made a mistake is that he underestimated me,' Hollande said in an interview on RTL radio. 'In politics, he who underestimates is too confident in himself and commits an error of judgment.'

Having lagged the blander but more popular Hollande for weeks now in polls, Sarkozy's best hopes of clinching a second term hinged on winning the support of around 80 percent of Le Pen's voters for Sunday and at least half of Bayrou's.

Bayrou objected to Sarkozy's lurch to the right.

'The line Nicolas Sarkozy chose between the two rounds is violent. It contradicts our values,' the centrist said, explaining his decision to reject the incumbent who is closer to him politically than Hollande.

Sarkozy recalled that Bayrou had not voted for him in 2007 and put his decision down to personal 'bitterness'.

Hollande welcomed Bayrou's backing but ruled out forming an alliance with him or giving his party posts in the government should he win the election.

'He (Bayrou) could have stuck to not voting for Nicolas Sarkozy,' Hollande said. 'But he went even further and I think he can convince men and women who are not on the left.'

Compounding a black week for the president, Sarkozy came across as agitated and tense in the nearly three-hour debate and failed to land a knockout blow on his challenger, who appeared more poised and confident.

Several surveys of people who watched the debate found that most felt Hollande was more convincing than Sarkozy. – Reuters