He emphasises his demonic nature and backdates his long-conceived treachery to the time when Jesus was still teaching

He emphasises his demonic nature and backdates his long-conceived treachery to the time when Jesus was still teaching beside the Sea of Galilee. He adds colourful details such as Judas's meanness - he balked at excessive expenditure on high-quality oil used to bathe Jesus's feet - as treasurer of the disciples.There are moments when Professor Klassen's explanation of what Judas did sounds like the defence of OJ Simpson - it is possible to produce endless hypotheses explaining his behaviour - but in the case of Judas some questions remain unanswerable. Did Jesus go to Jerusalem seeking his death? If so, how far did he cooperate with Judas in bringing this about? What were the motives of Judas? The last question has always fascinated writers, precisely because the Gospels leave it unclear why - the need for money aside - he became an informer.Where Professor Klassen breaks new ground is in showing that Judas's personality is a historical creation. In the narrative of the last days of Christ, the need for dramatic tension naturally tended to emphasise the role of Judas. But the most important impulse behind his demonisation was the political and religious needs of the young church after the fall of Jerusalem in 70AD as it became increasingly anti-Jewish.

Professor Klassen concludes: "The emerging church began to see the need to draw boundary lines and found Judas a convenient figure for he was both a Jew and had been a disciple."Volumes have been written about Judas but the New Testament has surprisingly little to say about him. Mark has just 169 words on him, Matthew 309, Luke and Acts 233 and John 489 Saint Paul does not mention him at all. Almost all that is said about him deals with the week before the Crucifixion in Jerusalem. The early church was interested in the relations between Jesus and God, not the motives of the man who led the soldiers to Gethsemane. It is only in John, written at a later date, that the character of Judas is given colour and he is shown secretly plotting the betrayal of Christ.Outside the Gospels there is no evidence of Judas's existence. Scholars have been frustrated to find that the second part of his name, Iscariot, gives little hint about his back-ground Despite immense efforts its derivation remains uncertain. It might mean that Judas belonged to the Sicarii, a branch of the anti-Roman radicals, the Zealots.

More prosaically it might mean that Judas came from the village of Kerioth in Judea or that he was a dyer or a fruit-grower. Iscariot might even have been added to his name after the Crucifixion of Jesus and could mean, from its Hebrew root sakar, the "one handing over".Judas is associated with two places 15 minutes' walk apart in Jerusalem. One is the garden of Gethsemane with its ancient twisted olive trees on the lower slopes of the Mount of Olives, visited by hundreds of thousands of pilgrims every year. Almost wholly unfrequented is the site of Akeldama, the "field of blood" bought with the 30 pieces of silver paid to Judas, which, according to a fourth-century tradition, lies at the bottom of a steep valley below the south wall of the Old City of Jerusalem.It is a suitably gloomy spot, used as a rubbish dump by Palestinians from the Silwan and Abu Tor district. Wrecks of old cars, discarded children's clothes and black plastic bags litter the ground between the olive trees.