It has been condemned as theologically unsound by Westminster Abbey. Cardinal Tarcisio Bertone, a close associate of Pope Benedict XVI, has described as "shameful and unfounded" its thesis that the Roman Catholic Church covered up a secret bloodline descended from Jesus and Mary Magdalene. But Dan Brown's The Da Vinci Code appears to have had a spectacular impact in one corner of the establishment. Since its publication in 2003, applications for history of art degree courses at British universities have risen by nearly a quarter.
University departments acknowledge high levels of interest in the book, in which a Harvard symbologist investigates a trail of clues hidden in the works of Leonardo da Vinci, beginning in the Louvre with the Mona Lisa. A breathless plot has the hero avoiding a murderous albino monk and the clutches of a sinister underground Catholic plot, while gathering his evidence through interpreting works of art often found in churches.
Now, just as programmes such as Cracker and Silent Witness led to a big increase in applications to study forensic science, The Da Vinci Code seems to have inspired new generations to imagine themselves as the Inspector Morses of the art world.
"Three years ago I would have said that it was a declining subject," says Dr David Hemsoll, head of the history of art department at the University of Birmingham. "But recently more and more people are wanting to study it, and this could be something to do with The Da Vinci Code."
Dr Tom Henry, reader in the history of Italian renaissance art at Oxford Brookes University, agrees. "It has encouraged people to look again at Leonardo da Vinci, although courses involving him are enduringly popular." Oxford Brookes incorporated the book into its annual field trip to Paris earlier this year.
"We took extracts and talked about how Dan Brown had described the paintings and architecture," says Dr Nick Grindle, the lecturer who devised this part of the trip. "We went to the Louvre to look at how [the way] someone describes something can change the meaning."
Brown, he found, was not to be relied on: "He tended to describe things inaccurately. He misread really quite standard things, such as who was John the Baptist and who was Jesus in a particular picture."
Art historians are agreed on the "waywardness" of Brown's interpretations. "It simplifies to an extreme level what art history is about," says Dr Henry. "Really, The Da Vinci Code shows students how not to go about art history."
A qualification in history of art may lead to jobs in art, academe, heritage and conservation. Dr Hemsoll also claims that the subject is unique in teaching skills of visual analysis and discernment. "These are skills very useful for anyone in marketing and advertising," he says.
Some hope that the Da Vinci Code craze may correct the misconception that history of art is a soft option, a course for those endowed with plenty of money but not so many brains, which consists mainly of the languid perusal of beautiful paintings. Prince William initially decided to study the subject at St Andrew's University. "But Prince William switched from history of art," points out Dr Hemsoll. "It's a more demanding course than some people think."
The Da Vinci Code has sold 25 million copies worldwide, earning its author $140m, with more to come, no doubt, from the release of a film based on it, starring Tom Hanks and Audrey Tautou. Lincoln Cathedral agreed to allow filming there after Westminster Abbey refused.
"We cannot endorse the contentious and wayward religious and historical suggestions in the book," an Abbey spokesman said.
Meanwhile at the Sistine Chapel, one of the locations visited on the Da Vinci Code Tour, more tourists mean more money for the Vatican - although only a cynic, or a Dan Brown, would suggest that the church is excessively concerned with such worldly matters.