It could be the portrait of the Bard as ithers saw him.

A sketch, drawn more than 200 years ago and filed away in the archives of the Royal Scottish Academy for decades, is the real, previously unseen, likeness of Robert Burns, an art expert will claim at a major conference on the bard next week.

Drawn by Scottish artist and caricaturist John Kay in the late 18th century, the full- length portrait shows a man in country costume, albeit wearing a wig and shoes, leaning against a tree stump in a pensive pose, with a paunch and double chin, a large black hat upon his head.

It is a modest and realistic depiction of a rural gent, but not the Burns the modern world knows from the handsome and romantic bard depicted in his most famous portraits, notably that painted by Alexander Nasmyth in 1787.

Kay, who lived from 1742 to 1826, captured in nearly 1000 portraits and sketches the social whirl of Edinburgh at that time. From his barber's shop in Parliament Square, on the Royal Mile, Kay made etchings of the artistic set, the judiciary and academics, as well as the common man.

He was at the height of his artistic activity when Burns lived in the capital, overseeing the publication of his Edinburgh Edition in 1786 and 1787.

Fewer than 400 of Kay's portraits, sketches and caricatures have been identified and Sheila Szatkowski, an author and expert on Kay, believes the man at the tree stump is Burns.

Kay knew many of Burns's friends, and indeed drew them - including Lord Monboddo, James Hutton and Joseph Black - and academics believe it would be an unusual gap in Kay's collection if he had not drawn Burns. Ms Szatkowski believes this unsigned, undated and untitled sketch could be the Bard as he really was.

She said: "Although I cannot say this is definitely Robert Burns, I do not think anyone can disprove it. It is very strange that Kay has not be credited with a portrait of him, and this fits Burns's image as a farmer poet'.

"It is interesting when you look at the other portraits of Burns from the time - Nasmyth was a landscape painter, not a portrait painter and believed to be unhappy with his portrait of Burns. It was a favour for his friend, he did not charge for it and did not do a good job. We do not need to accept the Nasmyth."

Ms Szatknowski will present her claims at the Robert Burns 1759 to 2009' conference at the University of Glasgow, organised by the university's Centre for Robert Burns Studies, opening on January 15. The conference is the first major event of the Year of Homecoming and it is the first of at least four major European conferences celebrating the work of Scotland's favourite poet.

Last night Dr Gerry Carruthers, the director of the Centre for Robert Burns Studies, said: "I think it is 50/50 whether this image is Burns or not. It is not flattering but it is a caricature and it may be Kay was not a particular fan of Burns. I hope it will encourage discussion and debate."

Facing up to poet's image