I NOTE with interest David J Black's comments (Letters, August 6) concerning the discovery of the Shaw Burns portrait and his assertion that the nation does not need another Burns portrait.

First, I'd like to point out that the existence of this portrait was only made public slightly over two weeks ago by The Herald ("Unknown portrait of Robert Burns discovered at auction", The Herald, July 22) and news of a growing campaign to buy the portrait has not yet reached me here in Glasgow.

I have been researching this painting for the past seven months or so, as well as co-writing a book about Robert Burns in Edinburgh (to be published next year) and I'd like to clear up a couple of misconceptions about the Nasmyth paintings in general. Although the provenance of the original, now in the Scottish National Portrait Gallery, is reasonably clear, the same can't be said for the other two.

While I do believe they did come from Nasmyth's studio, there is no fully documented provenance I've seen which confirms this. We have the apocryphal story from Miss Cathcart who apparently saw the Kelvingrove painting hanging in Nasmyth's studio while receiving painting lessons, while conflicting stories have always plagued the London version. Indeed, when first catalogued in the Portrait Gallery in London it was as a Nasmyth/Raeburn, with both George Thomson and Nasmyth's sons giving differing versions of who actually carried out the work.

This version, the Shaw Burns, has come under the closest scrutiny of all of the portraits, having been examined thoroughly by several respected experts in their fields over a period of almost two years including comparison with the original and being subjected to modern technology through x-ray and infrared examination. It is also, I believe, the only complete and original portrait, with the original frame and glass. I would be fascinated with the results if the others were put under the same scrutiny.

I am also in no doubt that it went to Sir James Shaw; a helpful clue is that his name is written on the strainer. His story fits exactly with the timeline of the Burns family, also fitting the ascribed date of the frame and glass and so on. Little of any detail is written about Shaw; however, my research confirms his involvement with the funds to build the monuments and his lifetime care for Jean and the children. This, along with letters I'm currently transcribing, will I am sure give recognition to Shaw as by far the most important character in the final chapter of the Burns story.

Far from being of little interest, I regard it as the most important of Nasmyth's copies, and also the earliest. It is the only painting of Burns, by an artist he sat for, to be in the public domain.

As to value. I do not own it and these are discussions I won't be involved in, but value for works of art are mainly subjective or driven by a "must-have" rarity value. Additionally, with a work like this, there is also an everlasting public interest and commercial value to be considered with earnings from rights that would come with ownership. Over a period of time this commercial value will be substantial.

If the portrait does go to a gallery or institution then it will never again come on to the open market regardless of how deep a prospective buyer's pockets are. If it does go to a private buyer, it may become part of a private collection, almost certainly abroad, without ever having been seen in public anywhere.

To answer David Black's question, does the nation need another Nasmyth portrait of Burns? Perhaps not in Edinburgh, but in Ayrshire, the land of both Burns and Shaw? I think it would sit very happily there.

Jerry Brannigan,

6 Coltpark Avenue,

Bishopbriggs,

Glasgow.