Signed by MacGregor himself ...

A spokesman for auctioneers Lyon and Turnbull said: "The letter is from his post-outlaw period and shows that he can write very well.

"It is also interesting in that it shows he is chasing the Duke of Montrose for money, when it was usually the other way about.

"It has gone to a Scottish industrialist, who wishes to remain anonymous, and will be kept in Scotland."

The spokesman said he understood that the letter might be given to a museum to be put on display, but said no plans had been confirmed.

Bids were lodged ahead of the auction from as far afield as the United States and Australia after the letter's owner, who remained anonymous, offered it for sale.

1745 Rebellion

It had been a family heirloom thought to have come into the possession of the Jacobite Earl of Seaforth, who fought beside the rebel Rob Roy at the ill-starred battle of Glen Shiel in 1719.

The seller's grandmother could trace her ancestry to the Earls of Seaforth, who were stripped of their title in the aftermath of the failed 1745 rebellion.

Also at the sale a copy of the Act of Union of 1707, which created the British state out of Scotland and England, fetched �3,400 from a private collector.

A letter from Samuel Pepys to William Penn, whose son founded the American city of Pennsylvania, fetched �850.