LABOUR MSP and ally of Jeremy Corbyn Richard Leonard is sounding out his support and "likely" to put himself forward as a candidate to succeed Kezia Dugdale over the coming weeks.

A source close to Leonard, a member of Campaign for Socialism, a group closely aligned with the pro-Corbyn movement Momentum, told the National the former GMB political officer in Scotland is "a strong likelihood" to fight the contest to become the new leader of Scottish Labour.

"Richard Leonard is very likely to stand. He's talking to people and looking at his base. There is a theoretical possibility he'll not do it but I think he's going to go for it," the insider added.

READ MORE: Corbyn's right hand man in Scotland rules himself out of bid to replace Kez

The Central Scotland MSP is one of the country’s most experienced trade unionists and also heavily involved in leftwing policy development.

Earlier this summer he organised a conference in Motherwell on Scotland's economy, part of the UK Labour's summer campaign ‘for the many’.

Shadow Chancellor John McDonnell was a key speaker at the conference.

Leonard also co-edited the Red Papers, a series of essays by a collective of activists: trade unionists, academics and politicians which it said sought to move away from the debate "over unionism and independence" .

The news that he is likely to put his hat in the ring comes hours after another key figure in the party MSP Neil Findlay, who organised Corbyn's leadership campaigns in Scotland, announced he would not stand in the contest.

Scottish Labour is beginning the hunt for its fourth leader in less than three years, after Dugdale's shock resignation.

Other contenders being talked about are the interim leader Alex Rowley as well as the Glasgow MP and former deputy leader Anas Sarwar.

Speculation is also mounting on whether MSPs Jackie Baillie and Monica Lennon will enter the contest.

Dugdale stepped down on Tuesday with immediate effect, saying her party needed "a new leader with fresh energy, drive and a new mandate" to take it into the next Holyrood elections in 2021.

Despite her differences with Corbyn - against whom she campaigned in the 2016 Labour leadership contest -Dugdale denied suggestions that she had quit before being pushed by the left wing.

And she insisted she left the party "in better shape than I found it", after taking on the job in the wake of the 2015 general election, which saw Labour lose all but one of its MPs in Scotland while the SNP enjoyed a landslide victory.

Dugdale, 36, is the third Scottish Labour leader to have resigned since the 2014 independence referendum, with predecessors Johann Lamont and Jim Murphy both having stood down, while Sarwar and Iain Gray have also served as acting leader since the vote on Scotland's future.

Corbyn paid tribute to her, saying: "I'd like to thank Kezia Dugdale for her work as Scottish Labour leader and the important role she has played in rebuilding the party in Scotland.

"Kezia became Scottish leader at one of the most difficult times in the history of the Scottish Labour Party, and the party's revival is now fully under way, with six new MPs and many more to come."

Labour managed to win back some of the seats it had lost to Nicola Sturgeon's SNP in the June 2017 snap general election, with the party now having seven MPs from Scotland.

With the constitution having defined Scottish politics in recent years, Dugdale has sought to give Labour a distinct position and the party now supporting a federal UK.

She also pressed Scottish ministers to use new powers over income tax north of the border to raise extra revenue, calling for a return of the 50p top tax rate for high earners and a 1p rise in the basic rate.

Dugdale announced that she was quitting days after Corbyn finished a high-profile tour of Scotland, including an appearance at the famous Edinburgh Fringe arts festival.

She had backed his opponent, Owen Smith, in the 2016 leadership contest, and voted for Yvette Cooper in the 2015 election which saw Corbyn take charge of the party.

But since his re-election as leader she had publicly backed him, supporting his bid to become prime minister in June.

Her resignation came the day after her birthday, with Dugdale saying being leader had been "a difficult but fulfilling challenge".

In her letter to Scottish Labour Party chairwoman Linda Stewart, she stated: "Too often our leaders leave in a crisis, with scores to settle. I love this party too much for that to be my way. There will be no press conference and no off-the-record briefing in my name.

"I choose to stand down because I believe it is best for me and best for Scottish Labour, at a time when we can be positive and optimistic about our future."

Referring to the death of Labour activist and motor neurone disease campaigner Gordon Aikman earlier this year, she said she had "lost a dear friend who taught me a lot about how to live".

She continued: "His terminal illness forced him to identify what he really wanted from life, how to make the most of it and how to make a difference. He taught me how precious and short life was and never to waste a moment."

Dugdale will continue as an MSP for the Lothian region, with Rowley set to take charge of the party in Scotland until her successor is found.

First Minister Nicola Sturgeon wished her well for the future, writing on Twitter: "We may be opponents, but @kezdugdale led her party with guts and determination and I admired her for that."

Scottish Conservative leader Ruth Davidson said: "Kezia deserves the thanks of her party for the tireless work she put in as leader of Scottish Labour.

READ MORE: Corbyn's right hand man in Scotland rules himself out of bid to replace Kez

"She was a tough and principled political opponent and, in challenging circumstances for her party, she showed huge determination and spirit.

"These last two years will be remembered as a time when all three of Scotland's main political parties have been led by women, and all there on merit.

"Kezia did more than most as leader of Scottish Labour to ensure that, in future, such a thing is no longer deemed remarkable, or of note. I wish her well for the future."