Labour launched its election campaign for Glasgow East on Tuesday after an embarrassing scramble to find a candidate that does not bode well for Gordon Brown's future.

Margaret Curran, selected as Labour candidate late on Monday, began canvassing for votes in the tough, deprived area - a traditional Labour stronghold the party risks losing due to dissatisfaction with the government and Brown.

"I understand that the Labour Party must step up to the challenge in front of us," Curran said as she launched her campaign.

Labour's campaign to hold onto the seat on July 24, which it won with a thumping majority of 13,507 over the pro-independence Scottish National Party (SNP) in 2005, got off to a troubled start when its chosen candidate withdrew citing family reasons.

That left the party scouting around for someone brave enough to risk their political future in a seat where unemployment is high and anger with the government is widespread.

Labour's opponents say Brown should be ashamed of his party's record in Glasgow East - an area with pockets of poverty where life expectancy is lower than the Gaza Strip and North Korea and where many live off state benefits.

"They were scared they were going to get stuffed," said one Labour MP when asked about the delay in finding a runner.

"When your leader can't even go up there to campaign for you, that's a signal," he added.

The by-election was triggered when the incumbent parliamentarian stepped down on health grounds.

Losing Glasgow East, following defeats in two other parliamentary seats and in local council polls in England and Wales, could prompt a leadership challenge at the party's conference in September, some Labour MPs believe.

Scotland was once Labour's fiefdom but the SNP became the largest parliamentary force in May 2007, ending 50 years of political dominance by Labour.

The Scottish Labour Party is even fighting the Glasgow East election without a leader after Wendy Alexander stepped down recently following controversy over campaign donations, adding to a sense of a party in disarray.

Labour lost a parliamentary seat in Crewe in May, once deemed safe Labour territory, and was pushed into a humiliating fifth place in the Henley by-election last month.