For centuries belief that the Shroud of Turin really bears the likeness of the crucified Jesus Christ had to be a matter of faith alone. Then in 1898 it was photographed for the first time, and suddenly the negative image revealed an astonishingly life-like wealth of detail of a tall bearded man horribly tortured with whip, nails and crown of thorns. Virtually overnight, the age-old faith of the pilgrims seemed to be vindicated. Surely this was the very image of Jesus?