THE frontrunner to become the next Scottish Labour leader is already facing a backlash over his wealth, children’s schooling and an “unforgiven” call for Jeremy Corbyn to stand down.

Millionaire Glasgow MSP Anas Sarwar, whose children attend a £10,000-a-year private school, has emerged as the favourite to replace Kezia Dugdale after she quit on Tuesday.

However some senior figures in the party believe his privileged background means he faces a credibility challenge preaching the party’s mantra of “For the many, not the few”.

Mr Sarwar also signed an open letter last year calling on Mr Corbyn to consider his position and “do the right thing” after a vote of no confidence by Labour MPs.

He also backed Owen Smith against Mr Corbyn in the ensuing UK leadership contest, and tried unsuccessfully to persuade his Glasgow Southside branch to do likewise.

Despite his hostility to Mr Corbyn, he is now pitching himself as a unity candidate.

Ms Sarwar, 34, whose father is the former Labour MP Mohammad Sarwar, is the richest of Labour’s 23 MSPs, thanks to a quarter stake in his family’s cash and carry business.

Company accounts show that in December 2015, United Wholesale (Scotland) Ltd was worth £11.5m, making Mr Sarwar’s share worth around £2.7m.

However in July last year, the firm bought back some of its own shares for around £1600 each, suggesting Mr Sarwar’s 3011 shares could we worth £4.8m.

Mr Sarwar has also attracted controversy for sending his children to Hutchesons’ Grammar in Glasgow, the same school he attended before training as a dentist.

One Labour source said: “I would be surprised if Anas’s money and school choice never came up. I’m also certain that his support of Owen Smith will be raised.”

It means Mr Sarwar faces a potentially bruising contest against a candidate from the Corbyn wing of the party.

MSP Richard Leonard, 55, who has strong trade union links, is the likely contender.

The other prospects on the Left, MSPs Neil Findlay and Alex Rowley, ruled themselves out.

Mr Rowley, who has stepped up from deputy leader to act as interim leader, said he lacked the essential requirement for the job - the burning ambition to be First Minister.

Neither Mr Leonard or Mr Sarwar has yet declared their candidacy, however Labour MSP Jackie Baillie was seen at one of Mr Sarwar’s warehouses yesterday, suggesting a campaign operation is already underway.

A source close to Mr Leonard also said his candidacy was “absolutely nailed on”.

The line-up is expected to become clearer after Labour MPs, MSPs and council leaders hold a previously planned away day in Edinburgh tomorrow.

The party’s ruling Scottish Executive committee is due to meet on September 9 to consider the rules for the election, which could last several weeks.

Pat Rafferty, Scottish secretary of the Unite union, Labour’s main donor, urged the party “not to act in undue haste on any succession plan” or rush into a leadership election.

He said: “This is not about the next four weeks. It is about the next four years. This is an opportunity to reflect upon what the Scottish Labour Party stands for. Let's seize it."

Ms Dugdale, 36, resigned with immediate effect after two years as leader, a period that coincided with the party coming third behind the Tories in Holyrood and council elections, before a slight recovery and six new MPs at the June general election.

Former leader Iain Gray tried to persuade her not to go, but she said she had made up her mind after a series of personal and political upsets.

In her resignation statement, she said she wanted to pass the baton to someone with the “fresh energy, drive and a new mandate” to take the party forward to the 2021 election.

Nicola Sturgeon said Ms Dugdale “did a tough job with a lot of guts and a lot of grace” and said Labour might come to regret losing her.

Tory leader Ruth Davidson said Ms Dugdale had “put in a huge shift in the independence referendum campaign” and another in charge of the Labour Party, adding: “There will be a lot of people right across the Labour family who will want to thank her for her time.”

Like Mr Sarwar, Ms Dugdale backed Mr Smith against Mr Corbyn for the UK leadership.

Although Scotland was the only part of the UK to support Mr Smith, the decision meant she was seen as fatally out of step with the party’s new direction.

A senior Labour source said Mr Sarwar’s support for Mr Smith, and in particular his decision to sign a letter supporting the failed coup against Mr Corbyn, remained “unforgiven”.

Another said: “There’s a serious barrier to him because he signed that letter, because people are not willing to forgive. It hung over Kezia. I think Anas would be exactly the same.

“There’s also an image problem [with private school]. But his bigger problems is going to be his politics, before we get to talking about his family and his children.”

Another senior Labour figure said: “Anas’s strength is being ideologically lightweight.

“He used to be vice-chair of [New Labour group] Progress, but then he saw how the party was going left and cut his links. He won’t be loved on the Left of the party, because they regard him as not ideologically sound. However he is a likeable and competent performer.”

Martyn Cook, chair of the Campaign for Socialism, said he wanted the contest to be about policies rather than personalities but he had “no doubt that certain people will take issue” with Mr Sarwar’s wealthy background and school choice.

“That might be something he brings on himself [by making it a personality contest]. It certainly wouldn’t be wise for him to do that.

"We’ve had enough of the personal story stuff. We want it to be about the big ideas.

“More crucially for us, he signed that open letter with other MSPs when Corbyn was looking vulnerable. His conversion recently seems based on election results.

“That might be more of an issue for the Corbynite members.”

Rhea Wolfson, a Scottish member of UK Labour’s ruling National Executive Committee, added: “Members are looking to a leader who is closely associated with the new kind of politics, who is unequivocally in support of the radical manifesto that was put forward in the 2017 election, and who is supportive of the direction Jeremy Corbyn is leading the party.

"People who signed that letter are going to be burdened with it.

“For me it’s about people’s politics. It’s about the choices they have made.”

Others on the right of the party warned the contest could end in a damaging lurch to the Left.

Former MP Gemma Doyle said: “This is a real danger moment for the Scottish Labour Party.

“We’ve had a period of stability and unity under Kez’s leadership.

“It would be a mistake for the Scottish Labour Party, and whoever the new leader is, to take a completely different direction to the one that Kez has successfully deployed.”

Asked if he feared a Corbynite takeover in the wake of Ms Dugdale’s resignation, another senior Labour politician said: “It certainly is. I fear the constant back-biting by those who demand ‘unity’ has sent Kez over the edge.”

Mr Sarwar and Mr Leonard did not respond to requests for comment.

Mr Sarwar, whose maiden speech at Holyrood railed against poverty, has previously denied being a hypocrite, saying last year: “I have a history of fighting poverty and inequality. My father came to the country [from Pakistan] with nothing and was a success. That's a story of what you can achieve in Scotland. I want everyone to have the chance to succeed."