Brown's campaign went into meltdown and he ripped up his itinerary to make a personal call on the pensioner, 65-year-old Gillian Duffy.

Brown spent over half an hour apologizing to her in private. In total he issued four apologies, including one to his party workers. However the apologies may not be enough to correct what is seen by many commentators as the worst gaffe in history by a British prime minister during an election campaign.

The Labor party was already suffering in the polls and looked set for defeat after the astonishing political breakthrough achieved by Clegg in the wake of his performance in the first live TV debate just over a fortnight ago.

Clegg's performance earned his party an immediate 10-percentage-point boost in most polls, forcing Labor into third place, a position they had never before been in during a general election campaign.

Clegg kept his supremacy over Labor after the second debate, although some polls in the run-up to this third debate gave Labor a slight lead over the Liberal Democrats.

Meanwhile, Cameron's Conservatives remained out in front through all the live debates, although their poll ratings are not strong enough for them to form a majority government.

In the last debate the only person who mentioned the bigot comment was Brown, who said in his initial address, "There's a lot to this job and as you saw yesterday (Wednesday) I do not get all of it right. But I do know how to run the economy."

Brown concentrated on his economic credentials and on attacking the Conservative plans to start cutting public spending this year. "Take money out of the economy now for ideological reasons and you put the economy at risk," he said.

Cameron attacked the government's record and said they had been too close to big finance. "Look at the Labor record. They hitched the fortunes of the economy to the City of London (the financial center of the capital). They gave Fred Goodwin (the chief executive of the Royal Bank of Scotland, which collapsed and had to be bailed out by the government) a knighthood for services to banking."

"He didn't just bring down his own bank he very nearly brought down the whole economy. We have stuffed these banks full of money and they are not lending. We need change to get our economy moving," he said.