A painting believed to be a lost masterpiece by Italian renaissance artist Raphael has been discovered at a stately home in Aberdeenshire.

The portrait hanging at Haddo House was until recently attributed to the little-known painter Innocenzo da Imola and valued at just a few thousand pounds.

The revelation that it may have been painted by Raphael means it would likely fetch millions at auction, with a sketch by 16th Century master selling for £29.7m in 2012.

If it is proven to be genuine, the "Haddo Madonna" would be the only publicly-owned painting by the artist in Scotland.

It was spotted by art experts Bendor Grosvenor and Jacky Klein during a visit to Haddo House for a new BBC series about lost masterpieces.

They also discovered a previously unknown landscape by French artist Claude Lorrain, whose work inspired the British artist J.M.W. Turner.

Dr Grosvenor said: "Finding a possible Raphael is about as exciting as it gets.

"This is a beautiful picture that deserves to be seen by as many people as possible. I hope 'the Haddo Madonna' - which would be Scotland's only publicly-owned Raphael - brings many people to this part of Aberdeenshire."

The paintings were both acquired in the 19th century by George Hamilton-Gordon, the fourth Earl of Aberdeen.

He bought the "Haddo Madonna" for about £20 under the impression that it was by Raphael but it was later decided the painting was actually by da Imola.

Jennifer Melville, head of collections at the National Trust for Scotland, which owns Haddo House, said: "We always knew that the collection at Haddo was very special, and the discovery of these wonderful pieces confirms its importance in the Scottish art world."