Harvard professor and economic historian Niall Ferguson has predicted independence would trigger recession and a drop in population as he pledged to apply for a US passport in the event of a Yes vote.

Mr Ferguson said the move would be necessary because his country, Scotland within the United Kingdom, would be "dead".

Mr Ferguson made his comments during a lecture tonight at a speech at Glasgow University, entitled "Kicking the life back into a dying mutual friend: A letter from America".

He told an assembled audience of more than 200: "(If Scotland votes for independence) my first act will be to apply for a US passport.

"Because my country, Scotland in Great Britain, will have been condemned to death."

He said that independence would lead to a "self-inflicted recession" which would trigger spending cuts and see immigration and Scotland's overall population both fall.

"Independence without monetary independence is no independence at all," he said, "as the eurozone crisis has shown us".

"I see Alex Salmond's economic plans as rather reminiscent of the plans that David Murray had for Rangers when he was at that great club".

He added that he mentioned Rangers because "I would have thought Glaswegians would have learnt something from those who have bold visions of the future but cannot make the books balance.

"And that would be Scotland".

He also accused the No campaign of being "unsuccessful" in persuading Scots to reject independence.

"Telling a Scot 'You can't do this if you do this terrible things will happen has been a losing strategy since time immemorial," he said.

"That's why I think the No campaign has been unsuccessful.It is not the way to persuade the Scots."

His case was, he said, the positive case for the Union.

He said the idea of the nation state was " profoundly unScottish" and that Scots had always been cosmopolitan and internationalist in outlook.

Scots were not the "victim" of British imperialism overseas, he said.

"Scots were in the engine room, and on the bridge".

His message did not go down well with all those listening.

John McKay from the pro-independence Business for Scotland told Mr Ferguson that he felt "deeply patronised and deeply offended" by his talk.