The boss of a supermarket chain said a vote in favour of Scottish independence would cause him to "panic", and blasted as "bollocks" a senior nationalist's warning of action against firms which oppose the move.

Iceland chief executive Malcolm Walker said a Yes vote would have "massive consequences" for the rest of the UK and suggested people had been too slow to wake up to the real possibility of a breakaway.

He predicted that by Thursday "common sense will prevail" and Scots will vote No but admitted he did not know what the consequences might be for his firm, which has 71 stores and a distribution centre in Scotland where it employs 2,000, if they did not.

Asked by Channel 4 News what his response would be to a vote in favour of independence, he said: "Panic!

"I know this is massively important to Scottish people but I suppose down here we've not really taken it too seriously. I don't think many people have considered for one minute that there would be a Yes vote.

"But all of a sudden now that's looking as though it could be likely. The consequences, I don't know, we are just going to have to decide what to do because there will be a big impact."

He gave short shrift to former SNP deputy leader Jim Sillars' warning that "scaremongering" business leaders will face a "day of reckoning" in the event of a Yes vote.

"Bollocks! Is that blackmail or a threat or what?" he responded.

"That is a stupid thing to say, 'day of reckoning'. What's he going to do, close us down?"

He said he was convinced the question would not arise in any case.

"Even though recent polls are predicting it's within a whisker and it might happen, I don't think it will. Common sense will prevail. We are Great Britain ... why would we want to break up and go our separate ways and become two smaller countries.

"We will lose influence. The consequences will be just massive so it won't happen."