SCOTTISH comedian Sir Billy Connolly has branded Rob Roy — one of Scotland’s most infamous heroes — a "murderer and a thief".

Rob Roy MacGregor, the most famous outlaw Scotland has produced, was considered a folk hero and a "Robin Hood" figure even during his lifetime, with King George I pardoning his crimes.

Born in 1671, he was son of the chief of Clan Gregor, later becoming the chief, and took part in Jacobite uprisings as well cattle droving, taking cattle from the Highland to the southern markets.

As his business failed, cattle he was supposed to deliver never appeared, and MacGregor went on to be an outlaw, before serving the British Government and spying on his clansmen.

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A fictionalised account of his life, The Highland Rogue, was published in 1723, and the novel Rob Roy by Sir Walter Scott was published in 1817.

As one of Scott's most popular novels, it has never been out of print in the more than 200 years since it was first published and provided MacGregor with a romanticised tale known to Scots today.

However, Connolly, 81, argues that MacGregor was "a spy" and should be thought of us a criminal rather than folk hero.

In his new book, The Accidental Artist, he wrote: “Rob Roy MacGregor, what a prick.

“He was a spy for the English against the Scots and a spy for the Scots against the English. He was a murderer and a thief.”

Connolly also reflected on a scene in the 1995 Rob Roy film, with Liam Neeson playing the title role.

In a chase scene, one of MacGregor’s men leapt over a fence, placed  cow dung into his mouth to as a way to track horses, and said: “They’ve been gone two hours Rob!”

Connolly said: “I am here to inform you that the people of Scotland do not tell the time by eating shit."

"My grandfather lived to the age of 96. I never once saw him reach into his waistcoat pocket, pull out a piece of dog shit, have a bite and say: ‘F***, is that the time already?’," Connolly added.

A professor of Scottish history at the St Andrews University has recently questioned why moderns historians have not "rumbled" Rob Roy, concluding MacGregor did commit fraud, blackmail and spied for the British government against Jacobites and his clansmen.

David Stevenson wrote: “There is no reason to doubt that Rob Roy would have preferred the Stuart cause to the Hanoverian.

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“But political principles were not his priority. He battled for survival for himself and his family. If that necessitated fraud, deceit, double-dealing and betrayal he was ready to act accordingly. In spite of this he maintained his reputation as a hero.

“He was talented at spinning his own image and got Highlanders to see him as a victim who bravely fought against the odds for survival.”

“Why have modern historians not rumbled Rob Roy?

“The answer is partly that they have ignored him because he did not play a significant role in Scottish history in his own lifetime.”