Portraits of Vincent van Gogh

[2] Lesley Stevenson, a conservator at the Scottish National Gallery of Modern Art, discovered it during an X-ray examination of their existing pieces.

[3] The portrait is covered under layers of cardboard and glue, which experts are searching for ways to remove in order to confirm its authenticity.

[4] They believe it was painted when van Gogh moved to France and learnt about the work of the impressionists there, an experience that influenced his more colourful and expressive style that is much admired today.

The X-ray image will be featured at a Royal Scottish Academy exhibit in Edinburgh and displayed using a specially made lightbox.

Several works were seized and sold/or destroyed by NS authorities including the self-portrait dedicated to Paul Gauguin, September 1888, which was seized from the Neue Staatsgalerie in Munich, part of the Bavarian State Paintings Collections, to be sold at auction in 1939 in Lucerne, Switzerland, while other works by van Gogh could remain in this collection, but were kept under lock and key.