An academic who joined the Better Together campaign in 2012 has claimed that people who vote Yes do so because they are not as educated as their No voting counterparts.
Jill Stephenson, who is a Professor Emerita in Modern German History, made the claim on social media site Twitter.
The academic, who is a prominent No activist, had previously accused Yes supporters of being less intelligent. However after facing demands that she apologise, the academic tweeted:
“I apologise unreservedly for using the term ‘less bright’ about yes voters. The point about a tendency to be ‘less well-educated’ remains.”
Stephenson’s remarks have led to outrage on social media with Yes supporters angry at the slur.
Several responses demanded the academic apologise, whilst others asked the No campaigner if she had any evidence to support her claims.
“I ask again Professor, is there anything that backs this claim? Is there any correlation between voter intent and education?” said one tweet.
Stephenson joined Better Together in 2012 and attended their inaugural meeting in Edinburgh. The academic also attended the inaugural meeting of Better Together Academics in Edinburgh in January 2014.
The row comes days after a Labour party candidate suggested Yes supporters were indoctrinating youngsters in a similar manner to that used by the Nazis in 1930s Germany.
Kathy Wiles, resigned as the Labour party Westminster candidate for Angus, after posting an image of German youngsters gathered under a Nazi banner. The image was an attempt to suggest that youngsters at a pro-Yes event were being indoctrinated in a similar manner to that which led to the creation of the Hitler Youth movement in Nazi Germany.
The claims by Stephenson are the latest in a series of offensive messages and comments made by leading members of the anti-independence campaign.
Better Together leader Alistair Darling recently compared First Minister Alex Salmond to late North Korean dictator Kim Jong Il. Mr Darling also expressed agreement when asked if the SNP was based on “blood and soil nationalism”, a slogan from 1930s Nazi Germany.