Auctioneers at Bonhams, the fine art house, are hoping that all the (mainly bad) news about the Royal Bank of Scotland and the debate about Scottish independence may have a beneficial impact on the demand for a portrait being sold next month in the firm's Edinburgh office.

Bonhams is auctioning a portrait of Archibald Campbell, third Duke of Argyll, the founder of RBS and one of 31 Scottish Commissioners who negotiated the 1707 Act of Union with England. The painting, which is estimated to fetch £20-30,000, is by Allan Ramsay, an eighteenth century portrait painter.

Chris Brickley of Bonhams said: “The emergence onto the market of this major work by Ramsay could hardly be more timely with RBS constantly in the news and vigorous debate taking place over the future of the Union between Scotland and England in which Campbell played a persuasive role.”

Ramsay enjoyed the Duke’s patronage and friendship for more than twenty years and painted him a number of times.

But surely if it’s newsworthiness we’re after ,there must be some more appropriate RBS-related candidates for portrait subjects.

Step forward anybody that owns portraits of the recently de-knighted Fred Goodwin or even the de-bonused Stephen Hester. It’s not obvious what the Goodwin work might fetch but it could easily be a collector’s item.