By Emma Griffiths and Brian Wheeler
BBC News at the Labour Party conference, Manchester
Gordon Brown has voiced his concern for workers in the financial industry
Gordon Brown has opened Labour's annual conference in Manchester with a pledge to do "whatever it takes" to sort out Britain's financial system.
The PM hailed the action his government had taken to help stabilise the money markets in the past week.
But he said he would now push for reforms to the global finance system.
It comes as a survey suggests Labour is facing a crushing defeat at the next general election while another poll has the Lib Dems eating into the Tory lead.
This week conference is being seen as a crucial five days for Mr Brown, and a chance to prove his authority by seeing off potential leadership rivals.
The conference got off to a good start for the prime minister, with the news that Harry Potter author JK Rowling had donated £1m to the Labour Party.
And Mr Brown was greeted by a standing ovation as he walked on stage at the Manchester Central conference centre, where he took part in a Q&A session with Chancellor Alistair Darling and four other ministers.
One delegate stood up to urge party unity - a reference to the 13 Labour MPs who have publicly called for a leadership election - and in a show of unity from the platform the prime minister was praised by several cabinet colleagues who said voters would not understand "navel gazing" at a time of economic turbulence.
We have absolutely the right team of people and we have the right leader in Gordon
In his speech, which opened the conference, Cabinet Office Minister Ed Miliband praised Mr Brown's "resolve, toughness and deep sense of fairness" and said the party had a "duty" to support its leader.
And chief secretary to the Treasury Yvette Cooper told delegates: "We have absolutely the right team of people and we have the right leader in Gordon, making tough decisions and leading us through what is really a tough time throughout the world".
Mr Brown said in the past week the world economy had been changing "almost by the day and almost by the hour".
He said when he got the call that HBOS was facing difficulties he realised "we are in a different world".
The PM's mood will have been lifted by the show of unity from his Cabinet colleagues and the support of ordinary party members. But three surveys paint a mixed picture for the party, with one suggesting a Tory landslide at the next election
His "first concern" was for people struggling with their mortgages, people worried about their jobs and mothers worried about food bills.
"So when people ask what we will do to sort out the financial system, what we will do to ensure there is responsibility and not irresponsibility I tell you in three words, whatever it takes."
He also said, once conference ended, he would go to the US to talk to financial institutions and other governments about "global financial supervision of what is a global financial system".
He said he hoped to get money back from Lehman Brothers to pay, not "high flying financiers" but the cleaners and other workers who otherwise would not be paid.
And he said other countries had followed after Britain temporarily banned short selling, and said his government had taken action to rescue Northern Rock and help people facing repossession, while the Conservatives would have left people "isolated".
Meanwhile three different opinion polls have suggested a mixed picture for the Labour Party.
An internet survey of almost 35,000 voters over 238 marginal seats for PoliticsHome.com, taken over three months up to the eve of the conference, projects a landslide victory for Conservative leader David Cameron at the next general election.
Its findings suggest the number of Labour MPs would be reduced to 160, lower than after the 1983 election and predicts eight cabinet ministers would lose their seat.
But a ComRes survey of 1,014 adults over two days for the Independent on Sunday suggested Lib Dem leader Nick Clegg's offer to cut taxes had boosted the party at the expense of the Conservatives - putting the Lib Dems on 21%, Labour on 27% and the Tories on 39%.
Meanwhile a YouGov survey of 1,200 Labour members for the Sunday Times suggested 53% thought Mr Brown was "indecisive and dithering" and just 34% thought he had an exciting vision for the future.
Earlier Mr Brown's financial competence was questioned by the chairman of Marks and Spencer, Sir Stuart Rose.
Sir Stuart told the BBC the government should have acted quicker when it became clear last year that Britain was entering a period of sustained economic weakness.
But more support for Mr Brown has come from the former Deputy Prime Minister John Prescott, who has launched a loyalist campaign together with former Downing Street press spokesman Alastair Campbell, MEP Glenys Kinnock and former minister Richard Caborn.
They have enlisted 20 Labour MPs, all of whom have sent letters to their parliamentary colleagues, urging them to "stand up and be counted" by joining the campaign.
The letters warn that internal party divisions will "serve the interests of the Tories".
As Labour delegates were arriving, thousands of anti-war demonstrators staged a noisy protest outside the conference centre calling on Mr Brown to end the "catastrophic" conflict in Iraq and withdraw British troops.
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