ONE of Scottish Labour’s biggest donors has backed Glasgow MSP Anas Sarwar to succeed Kezia Dugdale as party leader.

Property tycoon Alan Massie, who has ploughed in over £400,000 to the party, described Sarwar as the “natural leader” and a “potential First Minister”.

Dugdale’s shock resignation last week triggered Scottish Labour’s third leadership contest in as many years.

It is widely expected to be a two-horse race, with MSP Richard Leonard going up against Sarwar, who used to be the party deputy leader.

Neither MSP had confirmed their candidacy by the time of publication, but both politicians have been sounding out support in the last few days.

As of Friday, it is understood that around 31,000 people will be entitled to vote in a contest that will take up to ten weeks to complete.

At a party away day last week, MSPs were told that Scottish Labour has around 21,500 members and nearly 9,500 affiliated supporters.

However, the party may use the contest as a recruitment drive and allow new members and supporters to sign up within a short time period.

Massie, a successful businessman, has given around £400,000 to Scottish Labour, UK Labour and party candidates across the UK. He also bankrolled Dugdale’s leadership campaign in 2015.

However, he went cold on Dugdale during her spell as leader and urged her to “do more” to back the Union.

Speaking to the Sunday Herald, he said of the contest: “If Anas stood, Anas has got lots of qualities to bring the party together.”

The businessman said Sarwar is “knowledgeable” and has the “experience” to lead.

He added: "Anas is the natural leader of the Labour party in Scotland. I hope he declares...I do think he has got First Minister potential.”

Sarwar's opponents believe he has political drawbacks that could be exploited during a campaign. Not only is he is a millionaire, but his children attend a private school and he signed a letter last year calling on UK leader Jeremy Corbyn to consider his position.

Speaking to journalists ahead of the away day, he pointedly reached out to Corbyn: “What is in no doubt, is that whatever happens in the leadership contest, whatever happens after the leadership contest, I will work with all my energy day and night to ensure we return a Labour government across the UK with Jeremy Corbyn as prime minister and a Labour first minister in Scotland.”

Leonard, a Central Scotland MSP, is a highly-regarded trade unionist who would be expected to steer the party in a more socialist direction.

However, although Leonard is a Corbyn supporter, a friend said he is a “pragmatic” left-winger who is not doctrinaire.

Leonard is not a member of the Campaign for Socialism - the key left-wing grouping inside the party - and he used to be the election agent for former Labour MP Anne McGuire, a well-known centrist.

Leonard is expected to get the support of the largest trade unions affiliated to Labour, such as Unite, Unison and the GMB, the latter of which used to employ him.

However, party sources are concerned that a contest between Leonard and Sarwar will ensure Labour has an all-male leadership.

MSP Alex Rowley is deputy leader and has not indicated that he will follow Dugdale out of the exit door.