Random House UK, publisher of The Da Vinci Code, is being sued, at the time of writing, in London's High Court by two of three authors of a book (also published by Random House UK) from 1982, The Holy Blood and the Holy Grail. Michael Baigent and Richard Leigh are claiming that Dan Brown, the author of The Da Vinci Code published in 2003, stole their ideas and therefore breached their copyright. One of the fundamental tenets of international and national copyright laws is that ideas cannot be protected by copyright law. What are these costly court proceedings trying to achieve and why, and are they relevant to copyright in visual art?

Baigent and Leigh claim that 'the whole architecture' of their book was stolen by Brown, not that he literally copied passages of their published text. For example, a central theme of both books is that Jesus and Mary Magdalene were married, had children, and their descendants exist today. The Da Vinci Code is published as a work of fiction, The Holy Blood and the Holy Grail as a work of non-fiction and historical conjecture. There is an old saying amongst intellectual property lawyers, 'if there's a hit, there's always a writ', which appears to be true in this case. The Da Vinci Code has achieved phenomenal commercial success: it won the best book award at the British Book Awards 2006, had sold around 30m copies before this current High Court case, had been published in 42 languages, and has been turned into a $100m film, starring Tom Hanks, Audrey Tatou and lan McKellen, that will open the Cannes Film Festival 2006. Since the launch of this High Court action sales of both books have soared - leading some cynical pundits to speculate that the true reason for bringing this high media profile legal action, at a time of the imminent release of the The Da Vinci Code movie, is to boost sales of both books (marketed by the same publisher) and audience numbers for screenings of the film. Speculation that is fuelled by those who understand that copyright law cannot protect ideas.

Copyright is an economic right that has for centuries been given by legislation to authors of original works of literature, drama, music and art - but only if those works are manifest in a concrete form, such as a manuscript, play script, written or recorded musical score, or a 3D or 2D visual art work. In other words an idea - for a novel, a play, a song, a picture - needs to be expressed in a fixed physical form that is therefore capable of being physically copied, before copyright law gives to authors (or their employers) automatic rights to prevent their original forms of expression being physically copied; an idea that is not executed in such a physical form is not protected by copyright law. This means that ideas and concepts conveyed or connoted by or through original literary or artistic works are not protected by copyright law, only the original forms of expression of them. Duchamp's readymades, for example, convey and connote ideas and questions about the nature and content of art - the urinal, the hat rack, the phial of Paris air, the typewriter cover, the bottle rack - and these conceptual issues are not protected by copyright law: contemporary artists have been stimulated and affected by Duchamp's concepts, and have been free to appropriate all or part of them as they wish, and have done so - the idea is the essence of the work.

Since only original physical manifestations of an author's ideas or concepts are protected by copyright law (say, the shapes, forms, configurations, perspective, colours or lines of a painting) it is logical that copyright law requires those physical manifestations to be the author's original - meaning that they must not be substantially derived from another author's earlier original physical manifestation. In other words, authors become copyright owners of works only if they have been produced by their own - and not by use of another author's - independent skill and labour; accordingly, they must not have copied from someone else.

The same applies to literature. When writers puts words on paper, they employ skill and labour in choosing their words and the precise forms of expression of ideas; but the words, not the ideas conveyed or connoted by the chosen words, are protected by copyright law. As was first explained by Mr Justice Whitford in his seminal Parliamentary Report on the radical reform of copyright law in the UK (The Whitford Committee Report on Copyright, 1977), if a reader of those original words is stimulated by the ideas conveyed by them, and writes their own original words about those ideas, the original author should have no cause for complaint. But if readers of those original words reproduced them as if they were their own, the original author has every reason to complain, because only the original author should have the right to reproduce their own original words - if everyone were free to reproduce those words, they would be gaining something at the expense of the original author.

And so originality of expression, not of ideas, is a prerequisite for having copyright protection for works of literature and visual art. The first question is whether The Holy Blood and the Holy Grail passes the legal originality test, and is therefore a copyright work: the book is a work of non-fiction/historical conjecture, the words of which are undoubtedly original forms of expression and should pass the legal originality test - unless, as has been argued by Random House before the High Court, Baigent and Leigh stole some of the words they used: 'If some phrases are not mine, it is something I liked sufficiently to hijack it' (Leigh). Assuming they pass the originality test, the next question is whether Brown stole those copyright words from the book: undoubtedly he did not, because the copyright claim is that Brown used its main ideas (which undoubtedly appeared 20 years earlier) but not its words.

The stealing of ideas by artists has been a fact of creative practice for centuries. In contemporary times, for example, several completely unrelated artists have questioned whether the current advertising material for the Orange mobile phone network - involving different coloured paints being poured into a series of bottles, bowls and tubs - has stolen their ideas. Countless artists have made works involving that same idea, albeit differently expressed each time, but have no copyright claim on the idea, only in their own original expression of it.

There is an interesting judicial ruling that may help and encourage Random House. In 2005 Brown was sued in New York State by Lewis Perdue, author of Daughter of God published in 2000 and of The Da Vinci Legacy published in 1983. Perdue made plagiarism allegations against Brown similar to those of the authors of The Holy Blood and the Holy Grail; he claimed $150m in compensation / damages, and court orders to prevent further retailing of The Da Vinci Code and the making of the movie. He failed. The Judge decided that 'a reasonable average lay observer would not conclude that The Da Vinci Code is substantially similar to Daughter of God... Any slightly similar elements are on the level of generalised or otherwise unprotectable ideas.'

© Henry Lydiate 2006