Third of Labour members fear general election loss with Brown

The findings, in the week of Tony Blair's resignation as leader, came as Peter Mandelson warned the Chancellor to stick to Blairite policies when he takes over.

With Mr Brown due to launch his campaign for the leadership on Friday, he faces growing calls to show leadership.

The Chancellor has kept out of sight since last week, and is waiting for Mr Blair to confirm his departure before making a decisive statement on his plan for the party.

His aides are putting the finishing touches on what is due to be an opening salvo designed to show that he has overwhelming support for his leadership.

Campaign manager Jack Straw has been collecting pledges of support from MPs and is expected to produce a list of nominations that could account for more than half of the 352 Labour MPs.

A campaign machine has also been set up that will be coordinated from Westminster by Chris Leslie, the former Minister who lost his Commons seat at the last election.

Mr Brown's team are waiting to see whether a left wing candidate - MPs John McDonnell or Michael Meacher - get enough support from MPs to stand against him.

Next week the campaign proper will begin with Mr Brown touring the country to set out his stall in a series of keynote speeches.

The scale of the challenge he faces was illustrated last night by a poll commissioned by one of the candidates for the deputy leadership, Jon Cruddas.

The survey of Labour members by pollster YouGov found that nearly half of members - 49 per cent -reject Mr Blair's claim that the results were a 'springboard' for a fourth general election victory.

Labour lost power in Scotland and Wales, and was wiped out in councils across the south of England as the Tories won more than 900 seats.

The poll also found that more than a third of Labour members - 34 per cent - are now less confident that the party can win the next election.

Mr Cruddas, who has strong support among the trade uions but remains an outsider, said, "This poll provides us with a snap shot of party members' views. Tony Blair called last week's results 'a springboard'. Party members take a more sober view of things."

Earlier Mr Mandelson warned Mr Brown that there must be no retreat from Mr Blair's reform agenda.

The EU trade commissioner claimed Mr Blair had 'changed Britain's political weather for good' and voters did not want a return to the past.

"The public is ready for new personnel - not a fundamentally different direction," he wrote in an article for London's Evening Standard newspaper.

Mr Mandelson, one of Mr Brown's most bitter opponents within the party, He said there would be a temptation for the party to return to its old ways, but warned it would be a mistake to retreat to its 'comfort zones'.

"The biggest question for Labour's future will be whether the default position is to take or avoid risks; whether the politically correct will prevail over what is harder to sell to the party; and whether New Labour reforms will be continued as a bag of tricks and gimmicks or whether the hard-won changes of the past decade will be built upon with fresh vigour," he said.

Mr Mandelson said Mr Blair had always argued for the most radical changes while many in the party remained suspicious of his agenda of market freedoms and public sector reform.

"It does not flow from this that Tony Blair's conversion of the old ideological Labour Party to New Labour is going to be reversed now that he is leaving office," he said.

"It does mean, however, that the temptation will always be there to go back to the old ways of putting the party first and the public second, of talking to ourselves when we should be listening to others, with the result that the party will end up losing."