MHAIRI Black has accused Kate Forbes of “intolerance” because of her stance on equal marriage – saying the Finance Secretary had “alienated swathes” of voters.

In a full-throated attack on Forbes, the party’s deputy leader in Westminster said: “Kate hasn’t just jeopardised a lot of activists and members, she has alienated swathes of the population before she’s even started.

"We need, and should expect, better judgement, communication, and leadership skills if we are to ever convince others of independence.”

In a lengthy Twitter thread responding to Forbes saying she would have voted against same-sex marriage had she been an MSP at the time.

READ MORE: Kate Forbes takes early lead in poll of SNP voters' leadership preference

The Paisley MP said she doubted Forbes had the "judgement, communication, and leadership skills" to convince voters of the case for independence and attacked suggestions the scrutiny faced by the Finance Secretary were a "unionist media plot" as being "utterly fanciful at best and a dangerous conspiracy theory at worst". 

She wrote: A lot of people have asked me my views of the leadership contest. Truthfully, I have been incredibly hurt so far. Hurt originating with the statements [Forbes] has made and since stood by. I, like most people in Scotland, could not care less about someone’s religion.

"If your faith says you cannot drink alcohol, then don’t. If your religion says you cannot enter same sex marriage, then don’t. If your religion does not allow for abortion, then do not have one.

"However, the moment you use your religion to justify voting against me having access to any of the above, then it is you who is showing intolerance.

"What you practice in your own time, and how you subscribe to live your life is your business, but as a lawmaker, if you choose to allow your religion to try and deny me my basic human rights, then *you* make it my business.

The National:

"The idea that Kate is being ‘persecuted’, or that there is a ‘witch hunt’ or ‘unionist media plot’ against her is utterly fanciful at best and a dangerous conspiracy theory at worst.

READ MORE: Ash Regan would 'lead minority SNP government' if Greens left Bute House deal

"Holding candidates to account, and scrutinising what they have said themselves - on camera, voluntarily, as a pitch to be the next FM of Scotland - is not abuse.

"Had a candidate said they do not believe in racially mixed marriages we would rightly be horrified - so why is my marriage still considered fair game?

"How I, and others, are expected to have faith in a leader who unashamedly and publicly believes the love between my wife and I should not be legally recognised, is beyond me. 

"Where there has since been shallow calls for, and promises of tolerance made, I find myself thinking of what Humza has said and understood for years: I don’t want to be tolerated, I want to be equal.

"Kate hasn’t just jeopardised a lot of activists and members, she has alienated swathes of the population before she’s even started. We need, and should expect, better judgement, communication, and leadership skills if we are to ever convince others of independence."

Forbes came out in front of a snap poll of SNP voters - but most say they do not know who they think should take over. 

A survey of the party’s supporters, commissioned by communications agency The BIG Partnership, found 31% are undecided over who they want to see as Nicola Sturgeon’s successor.

Forbes leads among those who have an opinion, with 28% saying they would support her - followed by Yousaf on 20% and Ash Regan on 7%.

A spokesperson for Forbes's campaign declined to comment. 

Writing on Twitter on Thursday, Forbes said she felt "heartsore" her views on LGBT rights had hurt people. 

She said: "I will protect the rights of everybody in Scotland, particularly minorities, to live and to love without fear or harassment in a pluralistic and tolerant society. I will uphold the laws that have been hard won, as a servant of democracy."