The Pre-Raphaelites: Sanctity, sex and death in high definition Walking into Tate Britain's Pre-Raphaelites: Victorian Avant-Garde, almost immediately you encounter William Dyce's Joash Shooting the Arrow of Deliverance. Painted in 1844, it features a young semi-naked man, with a bow and arrow drawn. His skin is like alabaster. His taut stomach muscles cast a vertical shadow that leads the eye to a large dagger, encased in a glittering sheath, lying across his groin. This painting, so blatantly fetishising the physical beauty of the young King Joash, is all the more shocking for its apparent Christian narrative. Such fusion of sex and sanctity is not rivalled in British art again until John William Waterhouse indulges in the naked flesh of a stripped and martyred teenage Saint Eulalia, and then we have to wait for the great Salvador Dalí"s indulgent images of Christus Hypercubus or Christ of Saint John of the Cross. It's an arresting way to start a show. The early work of the young John Everett Millais is most riddled with sexual symbolism. In his painting The Woodsman's Daughter, an aggressive prepubescent boy clad in violent red thrusts a handful of strawberries at a young girl, suggesting the illicit sexual delights that adulthood might bring. In Mariana, his depiction of a deserted woman facing spinsterhood, a soft brown mouse scurries across the canvas, while a pointy, phallic salt cellar glistens in the background. Millais's The Bridesmaid is not on show, but here the same salt cellar is boldly presented in front of an undressed virgin, whose long, loose hair frames a face deep in sexual reverie. But that face and hair do appear in this exhibition, in the haunting The Blind Girl, where the subject's closed eyelids indulge a sun that reddens her lips and cheeks. A butterfly, the symbol of metamorphosis and inner thought, hovers on her shawl; a blade of grass is entwined between her fingers, suggesting a deeply sensual inner experience. But nowhere does Millais so brilliantly portray a profound inner psychological world than in the half-closed eyes of his drowning Ophelia, who dreamily embraces deathly water as if she were in the arms of a lover. Pre-Raphaelites. Their flower-drenched damsels, "radiant women who are at the same time the most desirable and frightening that exist," were prototypes for his own highly sexualised, man-eating wife, Gala. But it's only when an exhibition like this brings together so many works that you get the chance to see this. Presented en masse, you are left reeling with the unnerving, profound suggestions littered across these at-a-glance chocolate‑box paintings. The high definition with which the Pre-Raphaelites painted, depicting the tiniest details with utmost accuracy and saturating every inch of canvas with intense colour, adds significantly to their ability to unsettle. In his film Spellbound, Alfred Hitchcock turned to Dalí for his dream sequence precisely because of the latter's high-definition style. We imagine dreams are misty, Hitchcock argued, but in fact it's because they are so sharp and real that they are frightening. The greatest exponent of dream-like high definition in this show is William Holman Hunt. His bizarre Scapegoat stands awkwardly in a vivid crystalline desert flanked by luminescent, mauve hills that seems far more dreamscape than landscape. Then there's his Lady of Shalott, which seems to draw on the different rules of time and space that the unconscious mind can conjure when dreaming. Hunt apparently shows us a woman at the moment she gives in to her sexual desire, liberated from gravity, her hair floating upwards as if she were underwater, her gown billowing, her body turning and the threads from her loom snaking through the air in cinematic slow motion. If his Shalott is the ultimate erotic dream, Hunt's The Triumph of the Innocents is more nightmarish. Framed between a midnight blue sky lit by a glowing moon and a strangely soft, watery and reflective earth that seems to be burping up translucent bubbles from some magical bog, Hunt presents the hyper-real ghosts of slaughtered babies who, garlanded with DayGlo flowers, defy time and space to perform a slow, floating, spectral dance of death around the Holy Family. There has been criticism in some quarters that the Pre-Raphaelites were not perhaps as avant-garde as this show suggests, and in others that it's no longer surprising to cast them as such. Nevertheless, when I look at work like this, I'm still staggered by its boldness and modernity. Franny Moyle is the author of 'Desperate Romantics: The Private Lives of the Pre-Raphaelites