Lady Claire, who has owned Kinloch Lodge on Skye for 40 years, told The Herald: "Britain is the only country in Europe to charge VAT at its full rate of 20% for all hotels.
"France charges 5.5%, Italy 10% and Austria 8%. No wonder we have a reputation for being an expensive destination for holidays.
"For all tourist-related businesses, VAT should be no higher than 10%.
"This is the most urgent issue surrounding Highland hospitality today, where tourism is the lifeblood of the economy."
Lancastrian Lady Claire, who 43 years ago married Godfrey, Lord Macdonald of Macdonald and High Chief of Clan Donald, inherited the 45-acre Macdonald estate at Sleat in 1970 and built Kinloch Lodge into a Michelin-starred luxury hotel.
Speaking before the publication of Lifting The Lid, her memoir of the years she has lived on Skye as hotelier and cook at Kinloch Lodge, and said she and her husband had twice voted SNP but do not want independence.
She said: "Scotland is an exciting country to live in and several people have remarked to us how it feels as if it has more pride and confidence in itself. I give Alex Salmond and the SNP full credit for this.
"In 2006, when Godfrey told me he intended to vote for the SNP, we were both feeling disillusioned with devolution and that the Conservatives hadn't a hope in hell of ever being elected for at least a generation.
"The Labour MSPs were an uninspiring lot, kept in power by the LibDems.
"Godfrey wasn't alone in thinking that the SNP should be given a chance, especially given that the party was led by Alex Salmond.
"Richard Lochhead [Cabinet Secretary for Rural Affairs and Environment] has done so much to raise the profile of Scottish produce and increase food exports, and works tirelessly on behalf of local food producers."
Both voted SNP in the 2007 and 2011 Scottish Parliamentary elections.
However, she admits several of their acquaintances were scathing in their condemnation of the couple's decision.
She said: "Some people are very entrenched in their Conservative ways, but we told them, 'consider the alternatives'."
They had voted Conservative before, but she claimed David Cameron is a "huge disappointment" and is adamant that she would "never, ever" vote for the Liberal Democrats, saying: "I despise them. Nick Clegg doesn't belong on this planet."
By contrast, she has great admiration for Mr Salmond, and believes the SNP has been good for Scotland, especially the Highlands.
She said: "The SNP seems to understand the problems Scotland has, and the importance of attracting inward investment, although I can't stomach Donald Trump trying to dictate the Scottish Government's energy policy."
However, she stops short of wanting full independence for Scotland. She said: "We wait to hear how and when the referendum will be worked and worded. But I am sure the Scots will not vote for separation. I fervently hope not, anyway.
"I believe what powers Scotland has are enough, and fiscal, foreign and defence policies are better dealt with within the UK."
She admires John Swinney, Cabinet Secretary for Finance, Employment and Sustainable Growth, but still wants one person to be put in charge of tourism. She said: "John Swinney is a wonderful man of profound integrity and I respect and admire him, but tourism merits a cabinet secretary of its own and can't afford to be sidetracked by another portfolio."