Despite liberal protestations to the contrary, the freedom of expression is often circumscribed, even in democratic societies.

Take the current furore over Mel Gibson's film The Passion as an example. Although the movie has not been released, the actor is under severe criticism for his gory drama about Jesus Christ's last few hours on this earth. A committed and devout Catholic, Gibson decided to direct a film about the Crucifixion, and according to those who have seen the unedited version, has succeeded in producing a searing portrayal of the Saviour and his tribulations at Golgotha.

The problem is that, according to powerful Jewish voices, the film reinforces a negative image of them as Christ's killers, and might thus lead to heightened anti-Semitism. This, surely, amounts to acute paranoia. It is a historical fact that it was the Jews who brought Jesus before the Roman governor of Palestine, Pontius Pilate, and demanded the death penalty for heresy. Unwilling to provoke unrest in the colony, Pilate agreed and Christ was duly crucified. These are all historical facts, but the powerful Jewish lobby in America feels that Christians should not be shown the blood and the pain of their Saviour even two millennia after the event.

However, no sensible person would hold the remote descendants of the Jewish elders who precipitated the tragedy responsible for it. Surely enough time has passed for Christians and Jews alike to view the event in its historical context. But it is entirely possible that Gibson will be forced to make major changes in the final cut of a film he has financed himself. Even the New York Times and other heavyweights of the American media have lent their voices to the anti-Passion campaign.

From cinema, let us turn to music for our second example of intolerance and censorship. After the Gulf War, the Dixie Chicks, a trio of very popular Texan country and western singers, were touring London when one of them remarked on stage that after the American attack on Iraq, she was ashamed of being from the same state as President Bush.

When the Guardian reported this comment, it was picked up by an American music website, and all hell broke loose. Two of the biggest chains of radio stations with a combined strength of over 400 broadcasting houses refused to play the group's songs. Any number of right-wing writers and TV broadcasters condemned the women as traitors. They have received so many death threats that they have been forced to hire bodyguards. But they have refused to back down despite the fall in the sale of their records.

From country and western to children's books: Elizabeth Laird, the popular children's writer, has written a new book called 'A little piece of ground' based on several months spent in Palestine. Her hero is Karim, a 12-year old boy who dreams of being a footballer. One day his father is stopped and humiliated by Israeli soldiers before his family, and Karim starts dreaming of inventing an acid that would eat through the steel of Israeli tanks. It is the story of occupation and daily trials seen through the eyes of a young Palestinian boy who then joins the intifada.

Predictably, the book has come under vicious attack in Canada and the United States, with Jewish lobbyists demanding that the publisher withdraw the book. So far, MacMillan has refused to give in. Critics accuse Laird of writing a one-sided story which amounts to Palestinian propaganda. The author says she has actually toned down the book as the reality that she experienced in the Occupied Territories is so much worse than her portrayal.

Perdition, a play by Jim Allen was being rehearsed in 1987 when the official body sponsoring the play decided it could not support the production shortly before it was to be staged, although denying that it had given in to the Zionist pressure. The theme, supported by documents the playwright claimed he had seen, was that the Zionists had collaborated with the Nazis to refuse the majority of the German and other European Jews permission to migrate to the United States although Washington had agreed to accept them.

According to this version, the logic of the Zionist leadership was that if the majority of the European Jews settled in America instead of going to Palestine, it would weaken their case for the creation of Israel. This cynical policy cost millions of Jewish lives, so it is understandable that the Zionists would be very sensitive to the charges Perdition levelled. The play was finally staged in 1999 at the Gate Theatre after it had been substantially revised, although it retained basically the same theme.

What lessons are we to draw from all these examples? One is that no matter how liberal we claim to be, there are always some past events that we would rather forget. And if somebody has the poor grace to expose these skeletons in our cupboards, we will move heaven and earth to deny him a public hearing. Clearly, even the most open of democracies will place limits on the freedom of expression, specially when a powerful lobby demands it. However, this certainly does not equate to the brutal gagging of free speech that takes place in dictatorships and quasi-dictatorships around the world.

Mercifully, the press is relatively free in Pakistan, but cinema, theatre and television are still heavily and crudely censored. Many important themes central to our daily lives and our destiny remain strictly off-limits, and these limits are established as much by private-sector editors and producers as by the information ministry. These sensitivities diminish as a society matures, but we have a long way to go.