Auction circles are abuzz...

Booming art prices have managed to produce quite a few ‘treasures in the attic’ recently, and we could soon see another as a painting originally valued at $470 (300 pounds) is likely to fetch up to 3 million after Bonhams discovered it was actually by Velazquez, a Reuters report states.

The portrait of an unknown gentleman goes under the hammer, as London hosts a series of old master & British art auctions featuring precious works worth tens of millions of pounds. While the newly-discovered Velazquez work is not among the most valuable lots on offer at Christie's, Sotheby's and Bonhams, its story is the most arresting.

The painting of a balding man in black tunic and white ‘golilla’ collar was part of a collection of works attributed to 19th century British painter Matthew Shepperson which was consigned for sale at Bonhams. But the auctioneer suspected the portrait was by a different artist and had it sent to the Old Master Paintings department for further analysis.

Consultant Brian Koetser was brought in and their suspicions were confirmed by Peter Cherry, lecturer at the History of Art department at Trinity College Dublin. After studying the painting, including with x-ray technology, he decided it was by 17th century Spanish master and dated from 1631-1634 when Diego Velazquez was in Italy or shortly after the artist returned to Spain.

"The discovery of this lost treasure is a once-in-a-lifetime experience; it's exciting to be able to bring it to the world's attention," said Andrew McKenzie, director of old master paintings at Bonhams. Sotheby's also holds its main London sale of old master and British paintings, and expects a work by 17th Dutch artist Jan Steen to be the top lot at 4.5-6.0 million pounds.

A pair of works by 18th century painter Johann Zoffany, being offered as a single lot, have a combined value of 6-8 million pounds.Sotheby's expects to raise over 21 million pounds from the main auction and a smaller day sale. Christie's holds its main old master auction and has set a pre-sale estimate of 18-26 million pounds.