For over a year now, whenever I've been on a trip abroad, the bookshops in the airports have been filled with books by one author above all others: Dan Brown.

With the film version of The Da Vinci Code due to hit our screens later this year, the inevitable tie-in between film and book will lead to even more promotions for Mr Brown, although with over eight million copies of the book sold since its release in 2003, there must be other authors who hope that saturation point is not far off.

So what is it about Brown's books that have made them multi-million bestsellers?

Brown's two most popular books, Angels and Demons and The Da Vinci Code share the same protagonist, Harvard Professor Robert Langdon, who in each finds himself at the heart of a criminal conspiracy with more twists and turns than a bucketful of fusilli pasta. Add to this a clever, attractive female sidekick, throw in a murder or five, and set it all in an international capital city. As a final ingredient, pepper throughout with a filing cabinet full of pseudo-history and alleged fact, both mixed together with common knowledge to leave a reader feeling that they have just finished a history book inside a murder mystery.

A final feature common to these books is a seemingly venal hatred of the Roman Catholic Church. In Angels and Demons, the Church is presented as an organisation at odds with the rest of humankind and inhabited by murdering lunatics, whilst in The Da Vinci Code, a grouping within the church, Opus Dei, is given the Brown treatment with its members murdering their way through London and Paris.

Such is the perceived bias against Roman Catholicism, that Brown's books have prompted a protest from The Vatican, whilst millions of readers now subscribe to a "plot" by the Catholic church to subvert the truth of the Christian faith.

Although Brown himself is clear that the books are 'novels' and therefore works of 'fiction', this has not stopped readers taking his mixture of fact and hypothesis as Gospel truth when it comes to the Roman Catholic Church. The trouble is that, for many of these readers, Brown's books are their only source of information, not only about the Roman Catholic Church but also about the Christian faith. This is like a football manager trying to learn his craft by watching Footballers' Wives.

Whilst Brown thinks the books are "a positive catalyst for introspection and exploration of our faith" rather they have added to the underlying mistrust of the institution of the Roman Catholic Church.

Yet for those millions who both accept this and still manage to remain faithful in their daily inspired acts of kindness, charity and love, the depiction of their faith deserves better treatment than the one served up by Dan Brown.