CANNES, France – Most critics panned “The Da Vinci Code” on Wednesday ahead of the world premiere of the year’s most eagerly awaited movie.

Kicking off the annual Cannes film festival, Ron Howard’s adaptation of the Dan Brown bestseller was described variously as “grim”, “unwieldy” and “plodding”, though one reviewer bucked the trend and said “You’ll Louvre It!”

The cool reception was temporarily forgotten at a glitzy opening ceremony, where screen legend Sidney Poitier and Bollywood star Aishwarya Rai joined Da Vinci Code star Tom Hanks and the normally publicity-shy Brown on the red carpet.

Even before its general release on May 18 and 19, The Da Vinci Code generated controversy as Christians around the world called for it to be banned.

The novel has enraged religious groups because one of its characters argues that Jesus Christ married Mary Magdalene and had a child by her, and that elements within the Catholic Church resorted to murder to hide the truth.

In Thailand on Wednesday, a police-run censorship board overturned an earlier decision to cut the last 10 minutes of the film, but insisted the distributor add disclaimers stating it was fiction.

In Ireland, volunteers plan to distribute free copies of a special edition of The Irish Catholic newspaper outside cinemas showing The Da Vinci Code over the weekend.

A Vatican cardinal has called for a boycott of the picture, and the Indian government said it would show the movie to Christian groups before clearing its release. In the mainly Catholic Philippines censors gave it an “adult only” rating.

Howard and Hanks defended the film at a news conference, saying it was a piece of fiction. British actor Alfred Molina, who plays a Machiavellian bishop in the movie, blamed the media for creating controversy where there was little or none.

At a screening late on Tuesday in Cannes, members of the audience laughed at the thriller’s pivotal moment, and the end of the $125 million picture was greeted with stony silence.

Trade publication Variety had barely a nice word to say.

“A pulpy page-turner in its original incarnation as a huge international bestseller has become a stodgy, grim thing in the exceedingly literal-minded film version of The Da Vinci Code,” wrote Todd McCarthy.

Lee Marshall of Screen International agreed.

“I haven’t read the book, but I just thought there was a ridiculous amount of exposition,” he said. “I thought it was plodding and there was a complete lack of chemistry between Audrey Tautou and Tom Hanks.”

Lou Lumenick of the New York Post was far more upbeat:

“Ron Howard’s splendid The Da Vinci Code is the Holy Grail of summer blockbusters: a crackling, fast-moving thriller that’s every bit as brainy and irresistible as Dan Brown’s controversial bestseller.”

Critics say the controversy surrounding the film, and the fact more than 40 million people have bought the book, will ensure a strong box office performance, but they believe word-of-mouth is likely to hit sales later on.

The movie industry will be watching The Da Vinci Code particularly closely after the first two summer blockbusters — “Mission: Impossible III” and “Poseidon” — stumbled.

Howard had some advice for those who objected to the story.

“There’s no question that the film is likely to be upsetting to some people. My advice is … to not go and see the movie if you think you’re going to be upset.”

Ian McKellen, an openly gay actor who plays Leigh Teabing in The Da Vinci Code, tried to make light of the controversy.

“I’m very happy to believe that Jesus was married,” he said. “I know the Catholic Church has problems with gay people and I thought this would be absolute proof that Jesus was not gay.”

The opening ceremony and Da Vinci Code premiere kick off 12 hectic days of screenings, interviews, photocalls and partying in Cannes, the world’s biggest film festival.