Others argue the bust should stay in Scotland, and be displayed in a museum.

Art historians say the piece has cultural significance, and among the reasons for this is the story behind it.

Sir John, a member of wealthy family, was about 18 or 19 and touring continental Europe when he encountered Bouchardon in Rome.

Bouchardon, the son of an architect, was 30 and still trying to carve out a career as a sculptor.

The commission to create Sir John's bust was one of the artist's earliest pieces. Bouchardon would go on to create sculptures for French royalty.

Scottish Borders-based art historian Dr Bendor Grosvenor described the Invergordon bust as an exceptional piece of art.

He added: "Bouchardon was hailed as the greatest sculptor of the early 18th Century.

"Here is this work of art that has fallen into the lap of Highland Council for no money at all and it seems all they want to do is sell it for a lot of money to someone outside Scotland, when really there is no reason they can't lend it to Inverness Museum or National Galleries of Scotland or National Museum of Scotland."

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