Devout Catholic Donald Tsang Yam-kuen was quick to defend his decision to join the lucky few invited to see the Hong Kong premiere of The Da Vinci Code last night.

The chief executive admitted he had read the Dan Brown best-seller, but he was adamant that he neither believed the story nor endorsed the tale. He also said his religious passion would not be changed because of one movie.

Mr Tsang's comments follow a storm among some Christians about the central theme of The Da Vinci Code - that Jesus Christ was married to Mary Magdalene and they had children.

Research in Hong Kong universities on alternate views on the life of Christ is growing in popularity.

The film and the book have been banned in several countries, and some hardline churches are calling for parishioners to shun The Da Vinci Code to protest against the allegedly heretical storyline.

Mr Tsang would not even confirm whether he had enjoyed the best-seller or if he was looking forward to the film version. He claimed his attendance at the premiere was required as part of his duties as patron of the Key to Conservation gala.

"The movie is only part of the function," a spokeswoman for Mr Tsang said. "It will be followed by a dinner celebration, all in support of the Nature Conservancy and its Blueprint for Conservation in China Project."

Undaunted by the furore The Da Vinci Code has caused in Catholic France and the whole Christian world, the Louvre is offering guided audio tours of the museum backdrop it provided for the film of the novel, which opens in Hong Kong today. Called "Step Inside the Da Vinci Code" and costing £10 ($145), the audio guide targets the museum's 7.5 million visitors, including 5 million foreigners, and millions more who visit its website.

Louvre officials had kept their distance from the novel, which begins with the mutilated body of a curator being found in the museum with a pentagram traced on his stomach. But the opportunity to co-operate in the making of the film was a chance to put a positive cultural spin on it. They are not just capitalising on the museum's role in the movie to raise money towards its annual budget of €185 million ($1.8 billion). They are also cashing in on the novel's notoriety to attract a wider, younger audience.

Their enterprise puts a pragmatic perspective on the outrage and angry debate sparked by the novel's central theme, that Jesus Christ was married to Mary Magdalene and that they had children, and claims that author Dan Brown blurred fact and fiction. That debate is reflected in Hong Kong, across the spectrum of Christian belief, teaching and scholarship, as our report on the controversy on A14 today shows. The underlying themes are the strength of faith, tolerance and openness to alternative views. The Da Vinci Code controversy contrasts with the violence and vandalism that broke out in Muslim communities abroad earlier this year in protest against the publication in European newspapers of cartoons of the Prophet Mohammed. As Professor James Rice of Lingnan University says, the fact that we are having the debate without violence and intimidation calculated to stifle free speech testifies to the healthy nature of it.

The contrast is a reminder that free speech is a pillar of a democratic, pluralist, tolerant society. Take away that right, and the freedoms of a community are at risk. But it should also be remembered that there are limits to free speech. The Muslim protests were an example. The issue was respect. The Muslim faith forbids images of Mohammed. Publications ignorant or uncaring of this were not using their right to free speech wisely. This does not excuse excesses of Muslim outrage such as the destruction of European embassies in the Middle East, but the issues that gave offence were not comparable.

A survey commissioned by prominent British Catholics of people who have read Brown's novel found that they are now twice as likely to believe Christ fathered children. The Catholics accused Brown of dishonest marketing based on peddling fiction as fact. Such open debate is an example of how free speech strengthens democracy; censorship and book-banning do not.