Foreign Secretary David Miliband, seen as a possible successor to struggling Prime Minister Gordon Brown, has warned Labour to stop fighting amongst itself - or risk poll defeat.

Brown is under fire over his decision to scrap a 10 pence tax band, a move seen harming some of Britain's lowest earners who comprise Labour's traditional core vote, and over plans to extend the period terror suspects can be held without charge.

Writing in the News of the World newspaper, Miliband warned the party was now the "political underdog".

Brown's popularity has plunged since he took office last year over fears he cannot manage an economic downturn despite a successful decade as Chancellor and his party now risks a drubbing in local elections on May 1 - and losing power to the Conservatives in general elections due by mid-2010.

Research by pollsters Populus for the Sunday Mirror found Labour had dropped three points in less than two weeks, and now trailed the Conservatives by 10 points at 30 percent to 40 percent.

"Gordon Brown has strong values and convictions," Miliband said. "The route to victory needs us to do more. First, see the world through the eyes of the voters.

"People will only listen to our claims about what we have done right if we are candid about what we have not," Miliband said. "Employment has never been higher but people are worried about housing.

"Crime is down but people think crime has gone up. Universal nursery education has been delivered but more and more people are concerned about care for elderly parents."

Miliband - who is viewed as a possible successor to Brown - praised Brown's values, but said the party faced electoral defeat if party members argued among themselves.

An increasing number of Labour politicians have expressed unease about the decision to scrap the 10 pence tax band.

Brown had to interrupt a visit to the United States last week to call a junior minister and convince her not to resign over the issue.

He also faces a government rebellion in the next few weeks over plans to extend to 42 days the period in which terror suspects can be detained without charge.

The Sunday Times said it has seen a document showing that more than 50 Members of Parliament, include 10 former ministers, are expected to vote against the plan.