Yes campaigners have welcomed comments from the chairman of pub group Wetherspoons, stating there is "no reason" why Scotland cannot be a "very successful independent country".

The remarks from Tim Martin come amid reports that some retail bosses plan to publish a joint letter warning of price increases in their stores if the country votes Yes in next week's referendum.

Speaking on the BBC, and asked how independence would affect his company, Mr Martin said it is "difficult to say".

He continued: "There's no reason in theory why Scotland couldn't be a very successful independent country.

"New Zealand has got the same population, does very well, Singapore, a smaller population, incredibly successful economy, Switzerland does well.

"There is a lot of nonsense talked, particularly by businessman, also politicians, to say that it is impossible for Scotland to survive as successfully by itself."

Asked if, for example, the cost of a pint would go up under independence, he added: "Absolutely no sensible reason in the world. England has the highest taxation of almost any country in the world for alcohol duties, very high VAT... so no reason."

Wetherspoons has 70 branches in Scotland, with sales exceeding £100 million.

Scottish Finance Secretary John Swinney said: "Tim Martin's comments today are very welcome - confirming the strong business confidence in Scotland and showing the desperate Tory-inspired scaremongering of the No campaign isn't working.

"Tim Martin is absolutely right to say that the increasingly desperate claims of the establishment over the last few days are 'a lot of nonsense'.

"The No campaign has resorted to shameful attempts to talk down the Scottish economy - but this scaremongering is backfiring spectacularly as David Cameron's role is uncovered.

"The fact is that Scotland is a very attractive place to do business and will continue to be after a Yes vote, with an economic policy which puts Scotland first - designed to attract investment and create jobs - rather than one run by a Westminster establishment which will always put London and the south east first."

It has been reported that a letter written by Kingfisher Group head Sir Ian Cheshire, and signed by other business leaders, will be published in the coming days. The letter would follow warnings from John Lewis and Asda about price rises under independence.

Gordon MacIntyre-Kemp, chief executive of pro-independence Business for Scotland, said: ''I understand that Morrisons and Tesco are refusing to sign this retailers' letter and we've had Tesco say that price rises are entirely speculative.

"We are dealing here with something that is entirely speculative because there will be negotiations and prices may well go down in an independent Scotland if the circumstances are right.''

Asked whether David Cameron had been privately pressing business leaders to speak out about the potential consequences of a Yes vote, the Prime Minister's official spokesman said Mr Cameron had ''made no secret'' of his wish for anyone with concerns to make their voices heard.