Former First Minister Henry McLeish has predicted that Scottish Labour will retain all 40 of its Westminster seats despite two disastrous opinion polls.
He acknowledged that the party had “drifted” away from its social justice message in recent times but claimed its fortunes can be turned around.
Ms McLeish, who was first minister between 2000-2001, spoke out today in wake of the shock resignation of Labour leader Johann Lamont and her deputy Anas Sarwar which has triggered leadership contests.
A YouGov opinion poll published last week showed only 27% of 1,078 people said they intended to vote Labour in the general election in May.
The results suggest that Labour could be on course to lose 30 of its 40 MPs and another poll carried out by Ipsos Mori survey pointed to the SNP wining 54 of Scotland’s seats.
Mr McLeish said Scottish Labour must rediscover its purpose of social justice, secure more independence from the UK Party and come up with a more radical blueprint for a stronger Scottish Parliament.
Its devolution proposals would give Scotland the power to raise 40% of its budget, through increasing the tax-varying powers under the Scotland Act from 10p to 15p – potentially raising an extra £2billion.
However, its plan to devolve three quarters of income tax revenues do not go as far as the other parties, who support handing full powers over income tax to Holyrood.
Mr McLeish said it was “potential mistake” for Labour to team up with the Conservatives during the independence referendum.
“The campaign for the referendum was not wisely constructed because the Better Together campaign should not have included, in my judgement, the Conservatives,” he added.
“But the problems that have befallen the Labour Party are more significant than merely that potential mistake.
“I want people to accept that Labour has drifted over the last seven to ten years and have a bit of humility to say to Scots ‘look we did get it wrong’.”
Mr McLeish said the Labour Party as a whole must take the constitutional question “more seriously” and heal the rift between Westminster and Holyrood in order to “sing off the same hymn sheet”.
“I do not think for a minute that Labour is going to lose MPs,” he added.
“I understand that we talk about punishment and crises but none of that need happen and I believe there is a huge reservoir of support out there for Labour.
“We have drifted a lot but if we get our act together I think Ed Miliband’s position need not be undermined and we can send the same number of MPs to Westminster.
“I am hopeful that if we apply ourselves with a more radical view of where Scotland should be within the UK, and if we can get to a point where we are a more credible alternative, that will win through.”
East Renfrewshire MP Jim Murphy and Lothians MSPs Neil Findlay and Sarah Boyack are standing in the leadership contest but Mr McLeish refused to reveal who he was backing.
“I would rather see a platform of issues that the candidates talk about rather than at this stage suggesting this person is better than the next one,” he added.
Mr McLeish, 66, paid tribute to Better Together chief Alistair Darling who has announced he is standing down from Westminster next year.
He said he had “nothing but praise” for the 60-year old Edinburgh MP and he will leave a “powerful legacy” because he made a “huge contribution” to Scotland and public life.
Mr McLeish said he hoped that outgoing First Minister Alex Salmond, MSP for Aberdeenshire East, would continue to make as contribution to public life.
“People who are in their 60s, as Alex will be in December, are on top of things and we want to be helping the country and be involved,” he added.
“It would be a real tragedy if the former first minister, as he will be soon, does not have a significant role to play.
“It could be at Westminster, it could be elsewhere but everyone should be playing a bigger role as we move on.”