Dugdale accused SNP of "dirty tricks" over controversial nurse

Ms Austin, 50, who said she used a food bank because of the NHS one per cent pay cap, told Ms Sturgeon: “You have no idea how demoralising it is to work within the NHS.”

She immediately came under attack from SNP supporters, including former MP Joanna Cherry QC, who wrongly told the BBC the nurse was married to a Tory councillor.

Ms Cherry, the SNP candidate in Edinburgh South West, later took to Twitter to apologise.

The Tories claimed Social Security Minister Jeanne Freeman had egged Ms Cherry on.

However there was also scepticism about Ms Austin's claims.

Social media users pointed out her Facebook page included numerous pictures of her wining and dining, including recently in New York, while her 19-year-old daughter, Storm, posted pictures of herself at fee-paying George Heriot’s school as well as New York.

Ms Austin responded on Twitter: “BEWARE! It is now a true representation of your life if you put your high days & holidays on social media even if pd 4 by friends & family.”

She told BBC Scotland yesterday she had used food banks twice in moments of crisis.

Launching the Scottish Labour manifesto in Edinburgh, Ms Dugdale said the “tide was turning against the SNP” after its decade in office, and the TV debate had been a “watershed”.

She said: “It’s a message for Nicola Sturgeon: we’re fed up with your obsession with independence, and your indifference to what really matters to us.

“And what was the response of the SNP when confronted with reality?

“They 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.

“So here’s an idea for Nicola Sturgeon. Stop the muck raking. Stop the excuses.

“Listen to what the people of Scotland are telling you.”

Tory MSP Murdo Fraser, who was at the BBC Scotland debate, said Ms Freeman had been part of the smear.

He said: “I was sitting alongside Joanna Cherry as she claimed on the BBC that the nurse was the wife of a Tory councillor. She was being urged to say so by the Scottish Government's welfare minister Jeanne Freeman.

“It was a disgraceful episode and Nicola Sturgeon and her party should be thoroughly ashamed. This smear operation points to something endemic within the SNP.

“Its supporters talk over critics, not listen. And the nationalists will always try to play the man not the ball. This kind of behaviour is utterly unacceptable.”

Anti-poverty campaigners also came to Ms Austin’s defence, with the Poverty Alliance saying it was unfair to see her past spending as “evidence of either lying or fiscal irresponsibility”.

They said: “People move in and out of poverty, very few people remain in poverty throughout their entire lives. Items can also be gifts, bought on finance or with a credit card.

“People on low incomes deserve the same treats we all enjoy – very few of us can say we have never bought a treat when the money could have been better spent elsewhere.

“There is often a clear double standard when we talk about how people experiencing poverty spend their money – for those who are well off a treat is deemed just that – a treat.

“However, when people on low incomes do the same they are often deemed irresponsible and to blame for their own situation.

“By attacking someone online for saying they have had to go to a foodbank to feed themselves or their family, we reduce the likelihood of people experiencing poverty speaking out.

“People with lived experience are the experts but a stigma exists around poverty, and it is a brave and difficult decision to speak publicly about what it is like to live on a low income.

“People relying on foodbanks for food is a sign of societal failure, not individual failure, so let’s stop blaming people for their poverty and start addressing the structural issues that cause it.”

The PCS union, which represents 23,000 public sector workers in Scotland, said some of its members had used food banks and pay day loans to cope with the public sector pay cap, a cap Ms Sturgeon says is now “unsustainable”.

PCS National Officer Lynn Henderson said “Some politicians are completely out of touch. They have no idea the havoc and misery that austerity pay has wreaked on ordinary workers. “Recently, we are aware of members in serious rent arrears, relying on foodbanks.

“We welcome Nicola Sturgeon’s comments to look at ending the one per cent pay cap, and our members will make sure that happens.”

Campaigning in Perthshire, Ms Sturgeon said Ms Cherry retained her confidence.

She said: “She made a mistake, an honest mistake, and she apologised for that. 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 was absolutely entitled to raise the issue that she did and, as I said, she raised an issue that I think is one of the biggest in this campaign, the level and value of real wages, not just in the public sector but in the private sector.”

LibDem MSP Alex Cole-Hamilton said the SNP must condemn its “cybernat” wing.

He said: “The First Minister faced perfectly fair questions from a nurse, which she was unable to answer. Within minutes the nurse was set on by the online Nationalist army.

"It was ugly, but is typical of a movement which has always been intolerant of differing views and is now losing support. The First Minister must launch an immediate investigation into who sanctioned this 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.

''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.''