The piercing gaze is reminiscent of the Mona Lisa while the beard and mouth bear a striking similarity to the artist’s portraits of himself.

Italian researchers claim to have stumbled on the Holy Grail of the art world – a previously unknown work by Leonardo da Vinci, squirreled away for centuries in a private collection.

In a claim that will provoke intense scrutiny, they say that a chalk drawing depicting Christ is almost certainly the work of the Renaissance master.

The drawing, which is in the hands of private collectors and held in a bank somewhere in Lombardy in the north of the country, only came to light recently.

“It is a remarkably beautiful and refined work and I’m absolutely convinced it is a sketch by Leonardo,” Annalisa Di Maria, an Italian art historian who has studied the picture, told The Telegraph.

The sketch, in red chalk, is reminiscent of this self-portrait of Leonardo

Credit: Getty

The paper on which it is drawn has been subjected to laboratory testing and dates back to the early 16th century, she said.

Born in 1452 in the Italian town of Vinci, Leonardo painted The Last Supper from 1495-1498, moved to France in 1516 to work for King Francis I, and died there in 1519.

“There are lots of elements – the posture of Christ is typical of Leonardo, who rarely drew figures front-on but from an angle, so that they were facing the viewer from a three-quarters perspective. It has that dynamism and sense of movement that is typical of Leonardo,” said Ms Di Maria, the author of The Mona Lisa and its Meaning – Leonardo da Vinci and the Neoplatonic School, published last year.

“The rendering of the beard is practically identical to Leonardo’s self-portraits, as are the eyes. And the painting is in red chalk, which the artist used a lot, including in the sketches for The Last Supper.”

The sketch is in the hands of a pair of collectors from the town of Lecco in northern Italy, who in turn acquired it from a private collection, she said.

The Mona Lisa – Leonardo's most famous work

Credit: AFP

A 60-page study of the artwork will be presented at a press conference in Florence once Italy manages to bring the second wave of the coronavirus outbreak under control, she said.

It was not clear where the artwork had been hiding all these centuries, if indeed it is an authentic work by Leonardo.

Martin Kemp, Emeritus Professor in the History of Art at Oxford University and one of the world’s leading authorities on the life and works of the artist, was cautious about the Italians’ attribution.

He is wearily accustomed to outlandish claims being made about Leonardo – particularly in the wake of Dan Brown’s blockbuster The Da Vinci Code – and cautions on his website that “there is absolutely no historical evidence that Leonardo or other Renaissance painters hid secret images/messages/names in their paintings.”

But he said there could be some merit to this latest case. “I wouldn’t dismiss it out of hand but I simply can’t tell without seeing the drawing and the scientific evidence,” he told The Telegraph. “I would need to see if it is drawn left-handed. Leonardo drew everything with his left hand.”

The dating of the paper would also need to be scrutinised by independent experts. There was a possibility that the sketch could have been produced by a member of the artist’s school.

"There is quite a crop of paintings of Christ and Salvator Mundi that were produced by followers of Leonardo,” said Prof Kemp.

The Salvator Mundi was rediscovered a decade ago and attributed to Leonardo, but question marks still hang over the true extent of the artist’s involvement in the work.

One element of the new drawing pointing to the hand of Leonardo was the fact that it was drawn in red chalk.

“Leonardo was a great pioneer of red chalk, it was one of his favourite media,” said Prof Kemp, the author of Living with Leonardo and Mona Lisa: The People and the Painting.

“I’m not dismissing it but it has got a long way to go. It would be dangerous to write it off but even more dangerous to accept it at this point.”