DAN BROWN’S The Da Vinci Code may prove to be more than the novel that made his fortune. In a development that is unlikely to have been part of his literary game plan, The Da Vinci Code could also, thanks to High Court proceedings before Mr Justice Smith, be as notorious not merely for the money it has made its author, but for the way in which it redefines the law of copyright.

This week the multimillionare and reclusive author will be in court to defend his blockbuster in the landmark case. Brown’s publisher, Random House, is being sued by Michael Baigent and Richard Leigh, two of the three authors of an historical work published in 1982 entitled The Holy Blood and the Holy Grail. Its third author, Henry Lincoln, has not joined the suit, and by way of the kind of curious twist beloved by Brown, a different division of Random House is the publisher of The Holy Blood. The key claim by Baigent and Leigh is that Brown infringed their copyright by using the “architecture” of The Holy Blood in his own blockbuster.

Random House and Brown deny the claim, but there is no denying its ramifications if Baigent and Leigh prevail. A victory for them would be “calamitous”, according to the novelist Julian Barnes, whose Arthur & George is on the bestseller lists. All writers research, retell and reinterpret ideas, Barnes told The Christian Science Monitor: “This is how a writer instinctively operates. It’s just the same as if you’ve been told a story by a friend or something happens in your family. It’s all fair game.”

Fair game it may be, but matters take on a more serious hue in the High Court. In The Holy Blood, Baigent and Leigh argued that Jesus Christ survived crucifixion and escaped to France to sire a dynasty with Mary Magdalene; it is this hypothesis which, they say, forms the overriding “architecture” of their work, only to be “lifted” by Brown. In essence, therefore, the claimants are seeking to extend the law of copyright into uncharted waters. The legal maxim that “there is no copyright in an idea” is being tested, just as, in televisual media, there have been successive attempts to claim format rights in reality television shows.

Random House’s lawyer, John Baldwin, QC, told the High Court that Baigent and Leigh were seeking “to monopolise ideas at such a high level of generality that they are not protected by copyright”. While Brown has acknowledged the use of many and diverse sources in The Da Vinci Code, even, it is suspected, crediting Baigent and Leigh via the creation of an anagrammed character Sir Leigh Teabing, many lawyers agree that on the hearing so far — and there is still time to run — the claimants have a way to go before they win their case.

As Antony Gold, head of contentious intellectual property at Eversheds, says: “Cases involving copyright infringement are notoriously difficult to prove. The claimant needs to show clear examples of similarities and often has to narrow these down to specific incidents where an idea has been directly copied. The author, Dan Brown, has won previous cases of alleged copyright infringement and the High Court case may face significant challenges.”

Similarities there may be and some have been struck by them. But in response to media coverage, Brown took the opportunity to highlight at least one crucial difference: “One of the ideas in The Holy Blood — perhaps even the central idea — is advertised on the back of my copy of the book: ‘Is it possible Christ did not die on the Cross?’ This is not an idea that I would ever have found appealing. Being raised Christian and having sung in my church choir for 15 years, I am well aware that Christ’s Crucifixion (and ultimate Resurrection) serves as the very core of the Christian faith. It is the promise of life everlasting and that which makes Jesus ‘the Christ’. The Resurrection is perhaps the sole controversial Christian topic about which I would not desire to write; suggesting a married Jesus is one thing, but questioning the Resurrection undermines the very heart of Christian belief.”

Caroline Kean, a media law expert with Wiggin LLP, argues that the case illustrates trends in publishing generally: “A publisher must have in mind not only ‘traditional’ risks such as libel and copyright, but the new privacy rights including what is being referred to in the past year as ‘false privacy’. Add to that the courts’ increasing recognition of intellectual property rights in formats and the arrangement of ideas, and it is little wonder that publishers are finding themselves on the receiving end of legal claims.

“There is no suggestion that it is the case here, but there must be occasions where the sums generated by blockbusters such as The Da Vinci Code or the Harry Potter books are so huge that a claimant feels it worth trying for a slice, even if only as a result of a pragmatic settlement.” Or as they say in the film world, “where there’s a hit, there’s a writ”.

A cynic might also remark that in the wake of the publicity surrounding the High Court trial, sales of The Holy Blood received a healthy shot in the arm. Amazon, the online bookseller, reported that sales rocketed by 3,500 per cent the day the trial began. Given that damages for copyright infringement are to compensate a claimant for income that he would have earned but for the infringement, it is difficult to see Baigent and Leigh securing much by way of damages, should they win.

It remains to be seen whether the court will uphold Baigent and Leigh’s argument. Were they to prevail, critics of the claim say that ours would be a literary landscape whose innate intertextuality is denied, one in which writer’s block will be less a product of the creative process and more because of the fear of being sued.

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