AN UNFINISHED portrait of Mary, Queen of Scots, is believed to have been found hidden beneath a 16th-century painting during a major research project.

The image of a woman, which experts say has “compelling similarities” to other depictions of the queen, was discovered under a portrait of Sir John Maitland, the Lord Chancellor of Scotland between 1586 and 1595.

The 1589 painting by Dutch artist Adrian Vanson was among a number of works to be examined by conservator Dr Caroline Rae as part of research by the National Galleries of Scotland (NGS) and the Courtauld Institute of Art in London. Dr Rae was examining Vanson’s techniques when an x-ray picked up a lead sketch of a woman underneath the Maitland painting.

Researchers suggest Mary’s execution in 1587, two years before the date on the painting, may be why the artist covered over or abandoned the portrait.