Labour's only Scottish MP is set to join the contest for the deputy leadership of the UK party tomorrow, the Scotsman understands.
Ian Murray is expected to make an announcement putting himself forward for the post after being approached by fellow MPs.
In an email to Labour colleagues before Christmas, Mr Murray set out his pitch for the job, saying the party’s path back to power must "run through Scotland".
Following a meeting of the Labour National Executive Committee on Monday, the party confirmed that Labour's new leadership team will be announced at a special conference on April 4.
The NEC agreed an 11-week timetable for the contest to succeed Jeremy Corbyn and deputy leader Tom Watson, giving candidates a week to secure nominations from MPs and MEPs, and setting a two-day window to sign up ‘registered supporters’ who will pay £25 for a vote in the leadership election.
A party spokeswoman said that the postal ballot of members will run from February 21 to April 2.
"We are by far the largest political party in the UK with well over half a million members," the spokeswoman said.
"We want as many of our members and supporters to take part, so it has been designed to be open, fair and democratic."
Mr Murray’s announcement will follow the entry into the deputy leadership race of the favourite, shadow education secretary Angela Rayner.
In a speech at a community centre in Stockport, Ms Rayner highlighted her working-class background and claimed her own party had been "patronising" to many of its supporters for too long.
"I talk about my background because for too long I felt I wasn't good enough; I felt ashamed of who I was,” she said. “It took me time for that shame to turn into pride.
"Because I remember when I first spoke from the front bench in the House of Commons, a parliamentary sketch writer said I must have got lost from the set of Little Britain.
"It was another way of saying I didn't know my place.
"Maybe I don't. But I know the place I came from. It's here. Not Little Britain. Real Britain."
Taking questions after her speech, Ms Rayner proposed a Labour leadership duo of herself and Rebecca Long-Bailey - the leading contender from the pro-Corbyn left of the party.
“Me and Becky are two fantastic women,” Ms Rayner said. “We've had plenty of blokes from London before."
She said she "took offence" on behalf of her "good friend" Mrs Long-Bailey being described as the "continuity Corbyn" candidate by Mr Watson, adding: "She is her own woman and she will say what she stands for. She isn't Corbynism, she isn't Blairism, she isn't Brownism.”