To the untrained eye, it is a smudge. To experts at the V&A, it might just be a thumbprint of the great Renaissance master.

Conservators at the museum are exploring the possibility that a print on a 500-year-old wax figurine was made by Michelangelo himself.

The print became visible to the naked eye after the wax model was placed in cold storage during the pandemic.

Viewers of a BBC series, Secrets of the Museum, will be able to see it in close-up as V&A staff bring the sculpture back out for display.

Peta Motture, senior curator, said: “It is an exciting prospect that one of Michelangelo’s prints could have survived in the wax. Such marks would suggest the physical presence of the creative process of an artist. It is where mind and hand come together.

“He destroyed a lot of [the wax models] himself. A fingerprint would be a direct connection with the artist.”

The print is on the buttock of the figure, Model of a Slave. It was made around 1519 as part of a study for a large structure to adorn the tomb of Pope Julius II in St Peter’s Basilica.

The plan was scaled back to a more modest monument in another church, and the slave was one of several figures left out of the final scheme.

Very few Renaissance waxes have survived to this day because the material is unstable, according to Victoria Oakley, one of the V&A’s conservators.

She described the Michelangelo as one of the treasures of the museum, and said: “It was never intended to last, that’s what is quite charming and quite remarkable about it. The artist probably had no clue it would survive for several more centuries beyond him.”

Michelangelo destroyed many of his wax models, but some were saved by friends.

The figurine was placed in cold storage last year along with other waxes as Britain enjoyed an unseasonably hot spring and summer. 

Ms Motture told the BBC Two programme: “We get anxious when the temperature starts to rise above 25 degrees. Those waxes will start sweating and looking very uncomfortable.”

There were fears that the treasure could melt in the south-facing Wolfson Gallery while the museum was closed due to the pandemic.

It was brought out of storage after five months. Before going back on display, the conservation team inspected it, and Ms Oakley saw the thumbprint for the first time.

Model of a Slave has already survived one disaster.

In 1924, a visitor stumbled backwards into the display case while admiring a neighbouring sculpture, and knocked it to the ground. The glass smashed and the figurine’s limbs were broken into fragments.

A painstaking restoration began, with pins holding the reconstructed limbs in place. Ms Oakley described it as a “pretty amazing” repair job and said it was holding up well nearly a century on.

However, the overall condition is deteriorating as the additives which Michelangelo used to improve the malleability of the wax have seeped out, creating a bloom on the surface.

Secrets of the Museum begins on BBC Two on Tuesday July 20.