Demonstrators for and against the action in Iraq gathered outside the Kodak theatre, the traditional walk down the red carpet was scrapped and actors were ferried straight to the front door. Many actresses chose to wear black.

The organisers had feared that presenters and winners would use their 45 seconds in the spotlight to speak out about the conflict, but most were restrained. The most outspoken was Michael Moore, who won the Oscar for Best Documentary for Bowling for Columbine.

He launched a vituperative attack on President Bush, saying: “We live in fictitious times. We live in a time with fictious election results that elect fictitious presidents. We live in a time when we have a man sending us to war for fictious reasons. We are against this war Mr Bush. Shame on you. Shame on you.”

Adrien Brody, who at 29 became the youngest man to win the Best Actor award when he collected an Oscar for The Pianist, hoped for a peaceful and swift resolution to the war and for the safe return of a longstanding friend serving in Kuwait. “I hope you and your boys make it home real soon,” he said. Chris Cooper also made a plea for world peace as he won Best Supporting Actor for his role in the film Adaptation.

Catherine Zeta-Jones, however, steered clear of the war when she collected her first Oscar for her portrayal of the ruthless murderess Velma Kelly in Chicago, which won several awards. The heavily pregnant star, who was named Best Supporting Actress, said: “My hormones are too way out of control to be dealing with this.”

As the show opened, the host Steve Martin had tried to defuse the atmosphere of controversy that surrounded the 75th annual ceremony by making light of the circumstances.

“I expect you saw there was no red carpet tonight — that’ll send them a message.” he said, adding: “Everyone has been supportive of of my hosting tonight – except, of course, for France and Germany.”

The show’s organisers, anxious that the ceremony would not turn into an anti-war rally, had acknowledged that allowing artists to have their say was the price of avoiding a wholesale boycott of the event. Gil Cates, the producer, hoped that those invited to present awards would stick to an “ethical agreement” not to depart from their scripts, he was resigned to Oscar winners using their acceptance speeches to make anti-war remarks.

“People who present an award on a show come to present and it would incorrect in my view and inappropriate for them to make any changes to what they have agreed to say,” he said. “The nominee, on the other hand, has earned their 45 seconds in the sun and while I personally might prefer them to stick to the reason that they’re there, it’s their 45 seconds and within the bounds of good taste they can say what they want.”

A taste of what was to come was on display at the Spirit Awards for independent films this weekend which at times seemed like an anti-war rally. Michael Moore had used that occasion also to attack the war and Julianne Moore, who was nominated for two Oscars, said: “Fighting is not the answer. We teach our children not to fight.”

Susan Sarandon — who was among those in black for the Oscars — and her partner, the actor Tim Robbins, led a march to the Los Angeles CNN studios on Saturday to protest against the glorification of war. “How can I not speak out about what’s going on in the world today?” she said. “It’s frightening. It’s tragic. If I can make an impact by saying something I will.”

The British director Stephen Daldry, Oscar nominated for The Hours, intended to speak out if given the chance.

“I certainly will mention the war in my speech,” he said. “I think it would be impossible not to.”

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