The Turin Shroud was faked by Renaissance artist Leonardo da Vinci using pioneering photographic techniques and a sculpture of his own head, a television documentary claims.
A study of facial features suggests the image on the relic is actually da Vinci's own face which could have been projected into the cloth.
The artefact has been regarded by generations of believers as the face of the crucified Jesus who was wrapped in it, but carbon-dating by scientists points to its creation in the Middle Ages.
American artist Lillian Schwartz, a graphic consultant at the School of Visual Arts in New York who came to prominence in the 1980s when she matched the face of the Mona Lisa to a Leonardo self-portrait, used computer scans to show that the face on the Shroud has the same dimensions to that of da Vinci.
“It matched. I'm excited about this,” she said. “There is no doubt in my mind that the proportions that Leonardo wrote about were used in creating this Shroud's face.”
The claims is made in a Channel Five documentary, to be shown on Wednesday night, that describes how da Vinci could have scorched his facial features on to the linen of the Shroud using a sculpture of his face and a camera obscura – an early photographic device.
The programme says the fabric could have been hung over a frame in a blacked-out room and coated it with silver sulphate, a substance readily available in 15th century Italy which would have made it light-sensitive.
When the sun's rays passed through a lens in one of the walls, da Vinci’s facial shape would have been projected on to the material, creating a permanent image.
Lynn Picknett, a Shroud researcher and author, said: “The faker of the shroud had to be a heretic, someone with no fear of faking Jesus’ holy redemptive blood.
“He had to have a grasp of anatomy and he had to have at his fingertips a technology which would completely fool everyone until the 20th century.
"He had a hunger to leave something for the future, to make his mark for the future, not just for the sake of art or science but for his ego."
Art historian Professor Nicholas Allen, of Nelson Mandela Metropolitan University in South Africa, has called for more tests on the Shroud for the presence of silver sulphate, which causes a reaction with the sun's UV rays.
He said: "If you look at the Shroud of Turin as it appears to the naked eye, you see a negative image of a human being, and if you take a photograph of that you produce a positive image of that human being, which means the shroud is acting as a negative.
"That in itself is a very good clue that it was made photographically."
Radiocarbon dating in 1988 showed the cloth was made between 1260 and 1390.
The programme explains the theory that da Vinci's forgery was commissioned to replace an earlier version that was exposed as a poor fake, which had been bought by the powerful Savoy family in 1453 only to disappear for 50 years. When it returned to public view, it was hailed as a genuine relic, and experts say it was actually the artist's convincing replica.
American Professor Larissa Tracy, of Longwood University in Virginia, told the programme: "Da Vinci had the necessary skills. He knew enough about anatomy and about the physical muscular structure of the body. Da Vinci had all the skills to create an image like the shroud. If anybody had the capacity to work with camera obscura or early photographic technique, it was Leonardo Da Vinci."
However Professor John Jackson, director of the Turin Shroud Centre of Colorado, who believes the item dates from the time of Jesus's crucifixion, dismissed the programme’s findings and said the earliest known record of the Shroud appears on a commemorative medallion struck in the mid-14th century and on display at the Cluny Museum Paris, he added.
“It clearly shows clerics holding up the shroud and is dated to around 100 years before Leonardo was born. There is no evidence whatsoever that Leonardo was involved in the shroud.”
The professor believes the radiocarbon dating of the shroud was wrong because the sample was contaminated.