English Heritage claims to have found “compelling” evidence to support the theory that a mystery portrait is of Lady Jane Grey.

The identity of the woman dressed in black and white has been the subject of debate for many years.

If proved to be Lady Jane, who ruled England for nine days in July 1553, it could be the only known depiction painted in her lifetime.

Lady Jane was deposed by her cousin, Mary I, and was aged 16 or 17 at the time of her death.

The most famous image of her is Paul Delaroche’s 19th century painting which shows her blindfolded before the executioner’s block.

Hidden features

Research conducted by English Heritage, the Courtauld Institute of Art and Ian Tyers, a leading dendrochronologist, has uncovered previously hidden features in the mysterious portrait.

Using infrared imaging, the Courtauld found that the sitter’s costume was significantly altered after the portrait was first completed.

Where now it is subdued, in the past the dress was embellished, with the imagery suggesting more decorative sleeves and a more elaborate head-dress. The white scarf across her shoulders is believed to be a later addition.

“One line of thought is that these changes were a concerted effort to immortalise Jane as a Protestant martyr after her death with a less ostentatious image,” said Peter Moore, curator at Wrest Park in Bedfordshire, where the portrait is on display.

The dendrochronology analysis – or tree ring dating – of the painted oak panels dates them to between 1539 and 1571. A merchant’s mark, found on the back, is identical to a mark visible on a portrait of Lady Jane’s predecessor, Edward VI, suggesting that the wood came from a merchant who supplied royal portrait artists.

Iconoclastic attack

Experts also confirmed work undertaken by past scholars which showed that the eyes of the portrait had been deliberately scratched out at some point during its lifetime, the sign of an iconoclastic attack. A posthumous image of Lady Jane in the National Portrait Gallery was damaged in the same way.

Rachel Turnbull, senior collections conservator for English Heritage, said: “While we can’t confirm that this is definitely Lady Jane Grey, our results certainly make a compelling argument.”

The portrait was acquired in 1701 by Anthony Grey, 11th Earl of Kent, and remained for 300 years at Wrest Park, his family home. When the estate was sold in 1917, the work passed into a private collection.

It re-emerged for a 2007 exhibition and scholars debated its provenance, with one historian arguing that the portrait depicted Mary Neville Fiennes, Lady Dacre, a contemporary of Lady Jane. The painting has since returned to Wrest Park on loan.