A lost masterpiece worth tens of millions of pounds has been found on display in a historic country house in Glasgow - after being missing for nearly 400 years.
Art historians discovered the painting by the celebrated Flemish Baroque painter Sir Peter Paul Rubens in Pollok House in the city’s south side.
The priceless work was long believed by experts to have been merely a copy of a 17th century portrait by the artist of George Villiers, the 1st Duke of Buckingham, a lover of the Scottish king James VI.
However painstaking conservation work was carried out after it was spotted in Pollok House by the “art detective” Dr Bendor Grosvenor.
He previously rediscovered a long-lost portrait of Bonnie Prince Charlie by the Scottish artist Allan Ramsay in the vast art collection of a mansion house in East Lothian.
This week’s instalment of the BBC series Britain’s Lost Masterpieces will reveal how many of Rubens’ trademark techniques had been concealed by layers of dirt and "overpaint."
It will also show how detailed technical analysis of the painting was carried out to show it dated back to the 1620s and in the manner used in Rubens’ studio.
Experts at the Rubenshuis Museum in Antwerp are said to have confirmed the attribution of the painting to Rubens, who is widely regarded as one of Europe’s most successful artists in the 17th century.
Pollok House was donated to the city of Glasgow in 1966 by the Stirling Maxwell family, which had lived for six generations on the site.
Although Pollock House is operated by the National Trust for Scotland, the art collection is in the care of Glasgow Museums.
The Duke of Buckingham’s portrait is thought to have been purchased by Sir William Stirling Maxwell, an avid art collector, who owned Pollock House in the late 19th century.
Glasgow Museums has announced that the rediscovered Rubens painting will be going on display at its flagship gallery, Kelvingrove, on Thursday, the after the BBC Four programme is aired.
David McDonald, chair of Glasgow Life, which runs the museums service, said: “Unsurprisingly, we are beyond delighted to discover the painting is by Rubens, an artist renowned globally as one of the most important painters in history.
“Glasgow is proud of its extensive art collection, considered by many to be amongst the finest in Europe. Glasgow Museums strive to learn more about the artwork in our care and it has been a joy to work with Britain’s Lost Masterpieces to understand much more about this remarkable painting.
“We are excited to give as many people as possible the opportunity to see Rubens’ masterpiece in person. George Villiers, First Duke of Buckingham is sure to become one of the undoubted highlights of any visit to Kelvingrove.”
The BBC said Wednesday’s programme would see the Pollok House painting compared to a “rival portrait in Florence.”
Dr Grosvenor said: “The chance to discover a portrait of such a pivotal figure in British history by one of the greatest artists who ever lived has been thrillingly exciting.”
Karen Cornfield, property manager of Pollok House said: “This is such exciting news for Glasgow and shows what a great eye Sir William Stirling Maxwell had. Pollok House is packed with beautiful paintings that he collected over the years.
“We hope the BBC programme will encourage visitors to come to Pollok, explore the collection and to learn more about the family who brought so many great artworks to Glasgow.”
A spokeswoman for Glasgow Museums said: "We do not have a precise figure for this work of art as we have not instructed a commercial valuation.
"However, Sir Peter Paul Rubens is one of the most famous and sought-after artists in the world, whose work is now worth tens of millions of pounds.
"As we have no intention of parting with the work we do not have a precise estimation of its value.
"As a whole, the Glasgow Museums collection includes over 1.2 million objects valued for insurance purposes at over £1.4 billion."