But for coming out against Scottish independence, the Clydebank-born tycoon claims to have been attacked by "racists."
Mr Bannatyne, 64, was moved to declare his backing for the UK after an aide to Russian President Vladimir Putin branded Britain "just a small island that nobody listens to."
An enraged Mr Bannatyne took to Twitter to say: "We might be a small island but we are a great country made up of Scotland, England Wales & NI that should stick together as 1 & not separate."
That brought some mixed comments, with Mr Bannatyne telling one follower: "Thankfully most of us are not as defeatist as you."
But he replied: "Defeatist is the last thing Indy is about. Fiscal powers, democracy and a whole lot more for my kids Duncan."
Mr Bannatyne added: "Amazing, Russia slags us off, calls us a small country no one wants to listen to. I defend & get attacked by racists."
Last year, the Sunday Times Rich List estimated Mr Bannatyne's wealth at £430 million but he has now fallen out of the list.
Compiler Philip Beresford said he could not find enough assets to justify his inclusion.
Mr Bannatyne's financial setback follows a costly divorce from his second wife Joanne McCue, which was finalised earlier this year, and company losses that saw his fortune fall to £85m in 2012.
The former ice-cream salesman who became a multimillionaire suffered a stress attack last year which he blamed on his acrimonious split with Joanne.