Image caption Claire Austin (L) received an apology from Joanna Cherry (R) following the BBC Scotland debate

An SNP parliamentary candidate has apologised to a nurse who confronted Nicola Sturgeon over the NHS during a televised leaders debate.

Claire Austin told the SNP leader that she had been forced to use a food bank and that working in the health service was "demoralising".

Shortly afterwards, Joanna Cherry told BBC Scotland the nurse was believed to be the wife of a Tory councillor.

She later tweeted an apology, after it emerged that Ms Austin is unmarried.

Ms Cherry, the SNP's justice and home affairs spokesperson at Westminster, was one of the party's representatives in the spin room for the BBC's debate on Sunday.

The QC initially told the BBC: "I'm advised that the nurse who spoke is in fact the wife of a Conservative councillor - so she's probably best placed to know she'd be considerably worse off south of the border."

In her later tweet to the nurse, she said: "Sorry I was wrong about Twitter rumours. Entirely right that your voice is heard."

Ms Austin has been heavily criticised on social media since appearing on the debate.

In her first contribution she said she was a nurse who could not manage on her salary and had to use food banks. In a second intervention she raised the issue of nurses' pay rises - which have been capped at 1% since 2008.

Ms Austin asked Ms Sturgeon:"How do you expect someone to live on that?"

She added: "You have no idea how demoralising it is to work in the NHS.

"Don't come in on your announced visits, come in the middle of any day, into the middle of any A&E department, come on in and see what we're up against."

In response, Ms Sturgeon said the policy was in place because of a "really difficult period with public spending".

"As we see inflation rising, that policy is no longer sustainable, I accept that," she added.

Image copyright Joanna Cherry/Twitter

Her appearance sparked speculation on social media about her relationship to a Conservative councillor, and her personal circumstances. Some of these posts were retweeted by a number of senior SNP politicians, including MSPs and general election candidates, before later being deleted.

In addition to the online criticism, The Scottish Sun published photographs which it said showed Ms Austin drinking champagne and enjoying "swanky meals".

They have led some to ask why she needed to use a food bank.

In a series of tweets, Ms Austin said she earned a salary of £22,345 and suggested that the "high days and holidays" which she shared on social media were paid for by friends and family.

And in a post on Facebook, which has since been removed from public view, she said she was "truly saddened" by the comments made about her.

She added: "When I spoke tonight I spoke on behalf of ALL NHS staff, not just myself but ALL NHS staff, not just nurses but CSW's [clinical support workers], the backbone of many wards, HCA's [health care assistants], again invaluable, but the porters too."

Ms Austin said she was unmarried and explained that she was invited to take part in the debate after being part of a Question Time audience when her question about nurses' pay rises was not asked.

She went on: "I am sad, although in this climate not surprised, at the verbal attack and abuse I have suffered from other nurses tonight."

What was the TV debate exchange?

Media playback is unsupported on your device Media caption NHS nurse Claire Austin accused First Minister Nicola Sturgeon of not listening

In an interview with BBC Scotland on Monday, Nicola Sturgeon criticised the social media reaction to Ms Austin and gave her backing to Ms Cherry.

"She made a mistake, an honest mistake and she apologised for that," the SNP leader said.

"In terms of the wider social media reaction, I don't think it's acceptable to make judgements about somebody's background.

"The nurse on the debate last night was absolutely entitled to raise the issue that she did.

"She raised an issue that is one of the biggest issues in this campaign - the level and value of real wages not just in the public sector but in the private sector."

Meanwhile opposition parties have accused the SNP of attempting to "smear" Ms Austin in wake of the debate.

Image caption Nicola Sturgeon said she had "confidence" in Joanna Cherry

Image caption The SNP tried to smear Ms Austin, said Ruth Davidson.

Ruth Davidson, the leader of the Scottish Conservatives, said: "There was a public sector worker in Scotland who was challenging the first minister of Scotland and the first minister's team was running around behind the scenes trying to smear the person who was asking the question, as it it was illegitimate of her to ask it.

"Now the SNP has got form on this. We don't accept bullying in our culture and we should not accept it."

In a speech to launch her party's manifesto, Scottish Labour leader Kezia Dugdale said the nurse "shamed Nicola Sturgeon by exposing the reality of life under the SNP".

She added: "And what was the response of the SNP when confronted with that reality last night? The nationalists started a smear campaign.

"They tried their usual dirty tricks. But it won't work this time. Because more and more people are wise to the underhand ways of the SNP."

Image caption Alex Cole-Hamilton called for a probe into the online attacks on the nurse.

The Liberal Democrat's Alex Cole-Hamilton said Ms Austin had been set upon by the "online Nationalist army" and he demanded the first minister launch an immediate investigation into the "public mauling".

"Efforts to discredit the impartiality of a public sector worker went right to the top of the SNP, as shown by the comments made by Joanna Cherry, which were later retracted," he said.

''Freedom of speech, especially the right to criticise our political leaders, is something we must cherish. That is why the first minister must act now.''

The BBC had also faced criticism on social media about the selection of the audience.

In a statement, BBC Scotland said: "We select audiences for our debates which reflect widespread political views in accordance with BBC election guidelines."

It went on to add that audiences include both undecided voters and those who support political parties.

Are nurses in Scotland using food banks?