It is “The Da Vinci Code” versus “The Holy Blood and the Holy Grail”. London’s High Court is hearing a legal tussle between the authors, with blockbuster novelist Dan Brown accused of lifting ideas from the non-fiction work published in 1982. At the heart of the row is the extent to which a writer can use other people’s research. Media Lawyer Paul Herbert said: “The publishers of the Da Vinci Code are saying, ‘Look, all we have done is take the basic facts in the original work, the premise about Jesus and Mary Magdalene and turn it into a novel. There is no copyright in the facts that we based it on, so where’s the claim?”Michael Baigent and Richard Leigh’s “The Holy Blood and The Holy Grail” deals with theories that Jesus and Mary Magdalene had a child whose bloodline still exists. The Da Vinci Code, which has sold more than 30 million copies worldwide,explores similar ideas. The best seller is now being turned into a film. There could be disappointment for fans as the legal action may delay its scheduled release in May.