AN Scottish businessman and previous donor of the SNP has withdrawn his support for the party, after criticising it for pursuing income tax and stamp duty reforms that target high-earners.

Bill Samuel, who had previously gifted £25,000 to the party for its 2007 election campaign, is said to have ignored a request for support earlier in the month.

He also told the Times that the SNP had given "fresh meaning" to mediocrity and said that plans for a second independence referendum "smacked of betrayal".

Mr Samuel, a former chairman of Motherwell football club, said that the "great hopes of a nation will now fatally flounder in the mud of moaning and complaint".

The 73-year-old said that recent stamp duty reforms that force middle-class Scots to pay more to move home than people in England had sent "a chilling message to all who looked north to invest".

"It said in resounding tones that ‘Scotland is now closed for business’," he said.

He added that the setting of a lower salary threshold for the 40p higher rate of income tax than the rest of the UK in December "confirmed [his] earlier fears".

Of the SNP, he said: "Politics can be paradoxical and despite professing a profound understanding of how to build an economy, within days of sweeping to power they tragically brought a whole new meaning to mediocrity."

Political commentator David Torrance said that it would be a "significant blow", while Scottish Tory leader Ruth Davidson said it would be "devastating" for the party.

Samuel said that the pledge that the referendum was a "once in a generation" affair also "looks certain to be flagrantly overturned and thus smacks of betrayal".

An SNP spokesman said: "A Tory hard Brexit is a massive threat to Scotland’s economy . . . so independence must be an option to protect the country from the disaster of a hard Brexit if it is the best or only option."