'Phallic symbols' found hidden in famous Pre-Raphaelite painting 'Isabella' by John Everett Millais

The Pre-Raphaelites are to be re-examined in a new blockbuster show at Tate Britain - and experts have uncovered a dirty secret that may shake up the traditional image of the Victorians as prudes.

One of the works on show at the exhibition, which opens tomorrow, is the first painting by John Everett Millais as a member of the Pre-Raphaelite Brotherhood he helped found, called Isabella. One Tate curator has uncovered a hidden image in the painting which shows a character in the foreground with what appears to be an erection.

Isabella, painted in 1848 when Millais was just 19 years old, will force people to “shove aside their preconceptions” and “dramatically changes the way we see the work,” Carol Jacobi said. “It gives us a different view of the Victorians.”

The painting shows the character in the foreground on the left angrily leaning forward, with his leg outstretched and using a nutcracker. The sexual suggestion is produced by a shadow on the table.

Dr Jacobi said: “The shadow is clearly phallic, and it also references the sex act, with the salt tipped into the shadow,” before adding: “We can assume it’s deliberate, so then that raises the question: what’s it there for?”

It is also believed that the nutcracker and the character’s extended leg are also phallic references. She added: “This idea of one set of Victorian values is totally set aside. It was just like now; it was a society undergoing a dramatic transformation,” adding: “There was a bohemian part of society and the Pre-Raphaelites were on that side. They were experimental with lifestyles as well as art.”

Millais was the “golden boy” of the Royal Academy, she said, adding the sexual reference “is an example of how incredibly innovative and courageous” the artist was. “Once you have seen it, you can’t understand how people could miss it. The sexual imagery shows a wider engagement with what it is to be a physical human being. And an engagement with that was hugely problematic.”

“This is not a Freudian slip, or a hypocritical, furtive innuendo,” she said. “The imagery of masturbation and the anxieties around it and being unable to control yourself sexually would have been well known.”

Dr Jacobi is to publish a paper on the subject next month called Sugar, salt and curdled milk; Millais and the synthetic subject. She said the image of a salt cellar, which is also phallic, runs through a number of the artist’s paintings.

She argued that the image may not be as shocking as we may expect. “This sort of image would have been very familiar to Victorian men, not in painting maybe but the popular medical discourses of the day. Particularly discourses that warned against overindulgence, and self-abuse as they saw it.”

Isabella, which is on loan from the Walker Art Gallery in Liverpool, is a reference to the poem by John Keats, Isabella or the Pot of Basil, itself adapted from Boccaccio’s Decameron.

The Pre-Raphaelites were formed in 1848 as part of a stand against the art establishment of their day, inspired by early Renaissance paintings. The Tate exhibition Pre-Raphaelites: Victorian Avant-Garde is the largest survey of the group for over 25 years.

It will show over 150 works from leading members of the movement which also include Dante Gabriel Rossetti and Edward Burne-Jones. The well-known painting of Ophelia by Millais is also on display.

Both Lord Andrew Lloyd-Webber and Led Zeppelin’s Jimmy Page, are fans of Pre-Raphaelite artists and have lent works to the exhibition from their private collections.

It is the first time in over 60 years that a painting of The Lady of Shalott by William Holman Hunt is to be shown in the UK, while embroideries made for William Morris’ bed are on display for the first time outside Kelmscott Manor.