A former senior member of the Scottish Government has questioned whether SNP leadership contender Humza Yousaf has the “backbone” to take on the top job in Scottish politics.

Alex Neil, a former health secretary who was in charge of the legislation on same-sex marriage when it went through Holyrood, claimed Mr Yousaf had requested not to take part in that vote as he was coming under pressure from Muslim leaders, but did agree with the change.

His comments come after fellow leadership candidate Kate Forbes said she would not have backed the legislation for same-sex marriage had she been an MSP at the time.

Mr Neil told Times Radio: “There was a request from Humza because, in his words, of pressure he was under from the mosque for him to be absent for the vote.

“Alex Salmond as the first minister gave him permission to do that.”

As a result, Mr Neil questioned whether Mr Yousaf has the necessary “backbone” to be the next first minister.

The former MSP said: “I think Kate Forbes has proved that she’s got backbone. I question whether Humza has the necessary backbone to take Scotland forward.”

Speaking to journalists on Friday, Mr Yousaf said he missed the vote because of an “unavoidable” meeting with the Pakistan Consul General in Glasgow to discuss the case of Mohammad Asghar, who was placed on death row in Pakistan for blasphemy before being released.

He said: “I’ve said very simply, very upfront and honestly, it was an unavoidable meeting – not a meeting just to discuss policy or to have a chinwag.

“Anyone can see that not only did I vote at stage one, not only have I, as justice secretary, brought forward a hate crime Bill which extends protection for the LGBT community, I supported the GRR (gender reforms) Bill.

“Anybody who looks at my record, I think, speaks for itself.”

His comments came after nominations to be the next SNP leader – and therefore Scottish first minister – closed at noon on Friday.

Mr Yousaf, Ms Forbes and former community safety minister Ash Regan all secured the necessary support to make it on to a ballot of party members.

Ms Forbes’s religious views have dominated the first week of campaigning to succeed Nicola Sturgeon, and she came under further fire on Friday as SNP deputy Westminster leader Mhairi Black said she had been “incredibly hurt” by the Scottish Finance Secretary’s comments.

As she launched her campaign at the start of the week, Ms Forbes, a member of the Free Church of Scotland, said she would not have voted for same-sex marriage.

Ms Black, who married her wife last year, said with those remarks the Finance Secretary had “alienated swathes of the population before she’s even started”.

The MP continued: “We need, and should expect, better judgement, communication, and leadership skills if we are to ever convince others of independence.”

Ms Forbes, meanwhile, told how she wants to “lead Scotland into better days” – but also stressed the country must have tolerance as its “ruling ethic”.

She wrote in The Times: “If anything can be said of me in the past week it is that I am willing to be honest and open, even at the cost of my leadership bid and my career.

“I’m the only candidate with a strong grip on the economy and our finances.

“Looking at the cost-of-living crisis, and the unrealised potential of some of Scotland’s key industries, we need to focus on the economy.”

Mr Yousaf meanwhile promised SNP members he would be the first minister to take Scotland to independence.

Speaking after nominations closed, he declared: “I will be the SNP leader and first minister that takes our movement over the line and achieves independence for Scotland.

“We are within touching distance of that prize. It’s time for experience and unity to ensure that becomes reality.”

Ms Regan has promised to unite the party and the independence movement after claiming both have been torn apart by “petty differences and personal agendas”.

She accepted she is the underdog in the leadership contest, but speaking at her formal campaign launch she insisted: “I think I’m the only candidate on the slate that’s credible on some of the top issues that have been a problem for the SNP recently, that can draw a line under this so that we can all move forward together because we need to do that for the betterment of the country.”