Birmingham, England - Britain's Prime Minister Gordon Brown scrapped for his political future in the country's final TV election debate on the economy - the most combative showdown yet where he traded gibes with rivals a day after an embarrassing campaign gaffe.

He tried to smooth over the gaffe at the start of the debate Thursday. After forgetting to remove a microphone on a campaign stop Wednesday, Brown was heard calling a retired Labour voter a "bigoted woman" after she questioned him on immigration.

Thursday's debate offered Brown a chance to shine - the 59-year-old former Treasury chief is most comfortable talking about numbers. But his delivery fell flat. He looked tired from what some columnists have dubbed "Duffygate," referring to 66-year-old retiree Gillian Duffy.

"There is a lot to this job, and as you saw yesterday I don't get all of it right," Brown said. "But I do know how to run the economy - in good times and in bad."

The first U.S.-styled debates have spurred an unexpected transformation in Britain's politics and shaped the election, one of the closest in decades.

Months ago, the Conservatives' David Cameron was favored as the clear winner but he was surprisingly eclipsed after the first debate when Nick Clegg, leader of the perennially third-placed Liberal Democrats, stole the show with his affable yet confident persona. After Thursday's showdown, it seemed more likely no party would win a clear parliamentary majority with Clegg becoming a sought-after partner in a possible coalition.

Analysts, meanwhile, all but started drafting Brown's political obituary.

"It's the ultimate Shakespearean tragedy for Gordon Brown," said Frank Luntz, an American political consultant who has advised the Republicans.

Britain faces mammoth economic troubles with the one of the largest deficits in Europe - a 152.8 billion pound ($235.9 billion) sum racked up during the global financial crisis. Whoever wins the vote, it seems inevitable the country will feel the harshest cuts to public services since World War II. Taxes, meanwhile, are sure to rise and recovery measures could be stalled with a hung Parliament.

Cameron, the 43-year-old who studied economics and won an endorsement from The Economist, appeared to come out on top in Thursday's debates but analysts said polls in the coming days would give a clearer picture once voters digested coverage of the debates.

"I think Cameron came across as very strong," said Helen Coombs, deputy head of political research at the polling company Ipsos MORI.

"I thought Clegg's message was strong but I'm not sure he beat Cameron. I don't think Brown managed to turn himself around. He kept harping on about his achievements but this doesn't resonate with voters."

All three main parties have been reluctant to say what they plan to cut - answers that could lose votes. The final debate did little to explain details of economic recovery plans, but the showdown showed Brown and Cameron repeatedly trading blows over other's policies on tax, and potential cuts to welfare.

"This is a campaign where we are going to have to show ... that we want it more than anybody else," Cameron said after the debate.

Each candidate tore into each other over immigration - the one issue that has come in all three debates.

Some angry Britons blame an influx of 6 million foreigners since Brown's Labour took office in 1997 for worsening their plight. Immigrants - many from poor countries - have been accused of snatching jobs, pushing down wages and overwhelming welfare services.

Cameron wants a cap on immigration; Brown has championed controls through a point system; Clegg has suggested giving amnesty to illegal immigrants who come out of the shadows.

But it was the economy that dominated much of the debate.

"What you are hearing is desperate stuff from someone who's in a desperate state," Cameron said of Brown. In response, Brown accused his rival of plans that were "simply unfair and immoral," referring to Cameron's proposed cuts and tax plans.

Seizing another chance to ridicule both his rivals, Clegg pounced.

"Here they go again," quipped Clegg, recalling President Ronald Reagan's 1980 putdown of Jimmy Carter, when he famously said of his rival: "There you go again."

Victoria Honeyman, a political analyst at the University of Leeds, handed a victory to Cameron.

"Cameron did really well, Clegg was reasonable - not impressive, but reasonable," said Honeyman. "And Gordon Brown, in what was supposed to be his debate - in his backyard of the economy - didn't do well at all."

After a bruising 24 hours, Brown hoped to shine by showcasing his economic prowess - he has the most economic experience of the three, was treasury chief for a decade, and presided over much of Britain's recent growth.

Brown used opening skirmishes in the debate to remind voters of his handling of the economic storm, which included nationalizing some banks, and discussed fears that Greece's debt crisis could spread through Europe. Currencies and stock markets tumbled Wednesday on fears over Athens' plight.

"Economies in Europe are in peril, and there is a risk of dragging us into recession," Brown said.