The SNP leader has apologised for Mr Hay’s behaviour but is facing a growing clamour from political opponents to sack him after it emerged he was working for an SNP MSP while he posted the offensive remarks.
Mr Hay was the cybernat troll behind the “Paco McSheepie” Twitter account, which he used to launch anonymous attacks on opponents and voters.
He used the account to make offensive remarks while he was organiser for the SNP’s Edinburgh City Organisation and Yes Scotland Edinburgh Southern campaign, and continued to use it until this month.
During that time, he was also employed by SNP Edinburgh Southern MSP Jim Eadie, who paid him at least £4,500 in public money.
In his official pitch to be selected as a candidate for Westminster, Mr Hay said: “My reach to the public is broad and I have proved I can speak to all and engage openly, listening to and respecting opinions.”
But in his anonymous Twitter account, he had a different message.
He described pro-UK supporters, who accounted for 60 per cent of the referendum vote in Edinburgh, as “Quislings”, after the collaborator who ran Norway for Nazi Germany.
He also mocked elderly voters for “barely knowing their own name”, and claimed: “The generation who vote the same way because they always have done are dying off.”
Mr Hay deleted his Paco McSheepie account on Wednesday and apologised.
However, another tweet from Mr Hay’s official account has emerged from 8 April, when he questioned the “disproportionate number of non-Scots accents” in the STV Scottish leaders debate audience, quoting his “non-Scots wife”.
In 2010, when Labour sacked Moray candidate Stuart MacLennan for making offensive remarks about pensioners on his Twitter account after SNP demands he should go, the then- first minister Alex Salmond said: “Obviously it is the right thing that somebody who insulted all of Scotland’s old age pensioners can’t stand as a candidate.”
But under pressure yesterday, his successor, Ms Sturgeon, refused to take action. While it is too late to remove Mr Hay from the ballot paper, she has the power to suspend him from the party.
At First Minister’s Questions, she said: “I do condemn the language used and I condemn the comments made, as I always do when anybody steps out of line on Twitter, on Facebook or on any medium.
“Neil Hay has rightly apologised – and I think given that we face an election two weeks today, it’s up to the voters to decide.”
Scottish Labour deputy leader Kezia Dugdale said this wasn’t enough and claimed Ms Sturgeon had “failed the test of leadership”.
“This is a man who is categorically challenging the right of pensioners to vote in the general election,” she said.
Scottish Labour leader Jim Murphy also called on Ms Sturgeon to take the “unusual” step of sacking Mr Hay.
He said: “I know it’s an unusual step to take at this stage of the election campaign, but the SNP should sack this candidate. His name doesn’t belong on a ballot paper. This is a candidate who is not fit to take a seat in parliament.”
Liberal Democrat deputy leader Sir Malcolm Bruce said: “This is the sort of dirty tricks which undermine faith in democracy. These attacks and the half-hearted apology from an official candidate warrant condemnation from the top of the SNP. The ball is now in the court of the SNP, and the electorate of Edinburgh South.”
Miles Briggs, the Tories’ Edinburgh South candidate, said: “Voters across Edinburgh South will be shocked by the views expressed by SNP candidate Neil Hay and questions clearly must be asked if he is fit to serve in public office.
“Nicola Sturgeon has said she will not tolerate this sort of language and attacks on Scots – it’s time she proved that.”
Mr Eadie said: “Neil Hay undertook project work for me between December 2013 and March 2014. He has not worked for me since then. I was not aware of the tweets.”