First Minister Nicola Sturgeon was interviewing actor Brian Cox at the Edinburgh International Book Festival on Monday evening.
Brian Cox suggested that 'conditioning' was to blame for Scots lacking enough confidence for independence.
You can watch interaction here:
Pamela Nash, chief executive of Scotland in Union, said:
“I felt sick to my stomach when I heard these comments from Brian Cox, sat alongside Nicola Sturgeon.
“Their bizarre conclusions show just how detached both of these individuals have become. We have two prominent nationalist figures, one insulting the intelligence of Scots by saying they're 'conditioned', and another who says someone on the other side of the Atlantic has a clearer perspective than those who have to face the consequences of SNP incompetence every day.
“The not-so-thinly veiled ‘othering’ of English people by Mr Cox is at best divisive, and many would say even more serious than that.
“He claims that those of us living here in Scotland are lacking in confidence. What a lot of rubbish.
“Scottish people are not brow-beaten, we are a confident, successful people who are world leaders in many fields, not in spite of being in the UK, but by taking every opportunity available to us including as an integral part of the UK.”