Sarah Boyack in Scottish Labour leader bid

Lothians MSP Sarah Boyack is to stand for the party's leadership. Picture: Ian Rutherford

The former transport and environment minister put her name forward to replace Johann Lamont and fill the void at the top of Scottish Labour.

Ms Boyack threw her hat into the ring amid signs that the SNP intends to use the disarray engulfing Labour to grab as much power as it can for Holyrood.

Senior SNP sources believe Labour’s leadership vacuum will help the Nationalists present a convincing case to maximise devolution as they take part in Lord Smith’s commission on more powers.

Last night, MSPs backed a motion recognising the importance of all parties working together to agree substantial further powers for the parliament.

During a Holyrood debate on the Smith Commission, incoming First Minister Nicola Sturgeon said it would be “unforgivable” if the parties did not deliver devo-max – a settlement that would see all powers, save defence and foreign affairs, transfer to Edinburgh.

Ms Boyack’s candidature came as a surprise, despite her ministerial experience and her position as one of Labour’s original MSPs when Holyrood was established in 1999.

Until yesterday, her name had not been among the front-runners.

Jim Murphy, the Eastwood MP and shadow secretary of state for international development, is still the favourite to succeed Ms Lamont, who stepped down last week. The Blairite Westminster front-bencher has yet to officially declare, but an announcement is expected this week.

The other politician expected to stand is Neil Findlay, the Holyrood health spokesman who – as a representative from the left of the party – would expect strong trade union support.

When approached at Holyrood yesterday, Mr Findlay declined to reveal if he intends to stand against Ms Boyack.

Ms Boyack, 53, said colleagues in Edinburgh and London had indicated they would support her.

Referring to the referendum campaign, she said that the last few months had seen a “fantastic debate” about politics in Scotland, adding that a stronger

Scottish Parliament was on its way as a result of the Smith Commission.

Ms Boyack, who in 2011 conducted a review with Mr Murphy into the structure of Scottish Labour, said she wanted to move the debate on to how powers could be used best for the Scottish people.

“We need a lively debate, we need a robust debate, and we need to involve people across the whole country and reach out to the people that we have worked with over the last few months,” Ms Boyack said.

“There have been thousands of debates across the country. People have huge ambition for Scotland, and it is Labour, I believe, that can take those agendas forward and make Scotland the place it needs to be.

“It’s a great chance for the Labour Party to get back out there, talk to people and rebuild our movement and our message.

“So, that’s why I believe in putting my name forward. I can work with colleagues and I can take that debate forward. That is the key thing.”

SNP sources said they thought that Labour’s difficulties could work in favour of the Nationalists’ devo-max agenda.

As negotiations continue, many in the SNP believe Labour will be forced to adopt a more radical approach to income tax. It is the one party to have shied away from full devolution of income tax to Holyrood.

“Labour’s problem is that they have no sense of direction at the moment,” said one senior SNP figure.

“What is likely to hold most sway during this process is which parties know what they want and why they want it. So those parties which have got a coherent and reasoned argument are more likely to profit. Labour don’t seem to be in that position at the moment.”

• Anas Sarwar plays down Labour leadership concerns