The extreme religious sect which fuelled the passion of Mel Gibson

However, public interest in The Passion stems less from its "sand and sandals" epic qualities than from the religious controversy it has stirred up. The Passion unashamedly ignores the advice to film makers given by the legendary Hollywood producer, Samuel Goldwyn: if you want to send a message, use Western Union. In other words, don’t mix propaganda with entertainment. But that is precisely what Mel Gibson does in The Passion.

For Gibson is a passionate member of the Catholic Traditionalist movement, a minority (but growing) Catholic sect that rejects the reforms of the Second Vatican Council in 1964-65 - in particular the abolition of the Latin Mass. The Passion is nothing short of a party political broadcast for this movement, if only in the crude way Gibson’s earlier Braveheart was propaganda for the SNP.

How influential is this Traditionalist movement, and what might it do with a multi-million-dollar war chest from Gibson? The publicity surrounding The Passion has fed all sorts rumours - particularly of an anti-semitic nature. Much of this has been provoked by the increasingly bizarre public comments of Gibson’s 85-year-old father, Hutton. Gibson senior is a self-confessed anti-semite and Holocaust denier. In one recent radio interview, he claimed there were no Nazi extermination camps: "They [the Jews] simply got up and left! They were all over the Bronx and Brooklyn and Sydney, Australia, and Los Angeles."

He went on to claim: "They’re after one world religion and one world government. That’s why they’ve attacked the Catholic Church so strongly, to ultimately take control over it by their doctrine."

Gibson senior belongs to the extreme fringe of the Catholic Traditionalist movement which has gone so far as claiming that the Church in Rome has been taken over by a weird coalition of Jews and Freemasons acting for Satan. However such conspiracy theories are not representative of the Traditionalist movement as a whole.

Nor, it seems, Mel Gibson himself. He organised a private screening of The Passion at the Vatican - not something you’d happily do if you thought it was occupied by the Devil himself. However Gibson junior has maintained a discrete silence regarding his father’s racism. This may be down to filial loyalty but it has had the result of tarring him and the movie with his father’s nasty brush.

The Catholic Traditionalist movement is not a monolithic body, organisationally or doctrinally. Nor is it that big: of America’s 63 million Catholics, estimates of the number of Traditionalists vary between a low of 50,000 and a high of 100,000. They worship in some 600 chapels across the States, many of which are independent congregations. Traditionalists also refrain from eating meat on Fridays and women wear hats in church. Leaving aside the X-Files lunatic fringe, most Traditionalists are just ultra-orthodox Catholics. They vary between those who see the Vatican reforms as the work of foolish liberals who will eventually see the error of their ways, and a more conservative wing which sees the Vatican as genuine heretics.

Some of the Traditionalist breakaway groups have ordained their own bishops, which makes them schismatics in the eyes of Rome. One tiny group in Kansas has even elected its own Pope Michael. But most Traditionalists say they still "respect" the Pontiff in Rome and only disobey him because he leads a Church that has strayed from revealed truth. In return, the Vatican has tried to keep open the door to Traditionalists by relenting and allowing the Latin Mass to be used if the local bishop agrees.

The biggest of all the splinter Traditionalist groups is the Society of St Pius X, formed as far back as 1970. Its original aim was to train seminarians to keep alive the Tridentine Mass after it was replaced by the new liturgy after Vatican II. Originally the Society was unofficially tolerated by the Vatican. Only when the Society’s founder, the late French Archbishop Marcel Lefebvre, ordained his own bishops without papal permission in 1988, did the Vatican declare that he had committed a schismatic act incurring automatic excommunication. However, in the wake of numerous sex scandals in the mainstream Catholic Church, the Society of St Pius has attracted a growing number of adherents - it claims 20,000 members in the US. The Society is an ultra-orthodox Catholic movement which rejects ecumenism.

Mel Gibson is widely known in Traditionalist circles and has never made a secret of his religious beliefs: "I go to an all-pre-Vatican II Latin Mass," he told the USA Today newspaper two years ago. "There was a lot of talk, particularly in the Sixties, of ‘wow, we’ve got to change with the times’. But the Creator instituted something very specific, and we can’t just go change it."

Gibson does not belong to any of the larger Traditionalist groupings, but to an independent congregation, with some 70 members, called the Holy Family. Originally, most of the congregation attended Mass at another chapel which was then taken over by the Society of St Pius X. Gibson and others left in protest though the reasons for the split are obscure. Gibson then came up with $2.8 million to build and maintain a new Mission-style church complex in a little valley in the mountains north-west of Los Angeles, near Malibu Beach. According to public financial records, Gibson is its chief executive officer and its sole benefactor.

Is there anything to be feared from the Catholic Traditionalists, who are normally ultra-right-wing in their politics? Yes, says Professor Michael Cuneo, who studied their activities in his 1997 book, The Smoke of Satan. He thinks the Traditionalists "would like nothing more than to be transported back to Louis XIV’s France or Franco’s Spain, where Catholicism enjoyed an unrivalled presidency over cultural life and other religions existed entirely at its beneficence".

This prospect seems unlikely in Protestant America where the Christian Fundamentalists number in the millions. But the political importance of the Traditionalists, and especially of Mel Gibson’s propaganda movie, lies in the impact they might yet have on those 63 million mainstream US Catholics - the largest religious group in America. These Catholics are now deeply disenchanted with a clergy discredited by a host of sex scandals in recent years. Only last month, an official Catholic review board reported finding more than 10,000 cases of assault on minors by priests from 1950 to 2002.

Many liberal Catholics are leaving the Church in despair. On the other hand, Gibson’s movie is acting as a rallying point for many conservative Catholics inside and outside the Church. For instance, the Vatican official charged with bringing Traditionalist dissidents back into the fold, Cardinal Castrillon Hoyos, declared after viewing The Passion that it was "a triumph of art and faith" that would bring people "closer to God".

Part of the appeal of the movie to conservative Catholics in America (and elsewhere) is its source material. Overlooked in much of the criticism of The Passion is the fact that it is not actually based on the Gospels so much as on the visions of a forgotten 19th century mystic and stigmatic, Anne Catherine Emmerich. She claimed to have the gift of being transported back in time, which enabled her to supply details missing from the biblical accounts of the Passion. These were then written down and published in several best-sellers by the German poet Clemens Brentano. Very probably, Brentano embellished her account. For example, in the Gospels, Jesus is shown praying in Gethsemane, but the Devil is not mentioned. But in Emmerich’s visions, the Devil tempts Jesus as he prays. In Gibson’s movie, the Devil also tempts Jesus in Gethsemane.

The Passion is really about a return to a mystical, non-rational idea of religion, where life’s uncertainties can be avoided. It is a counter-revolution against ecumenism and against the attempt by Christians of all denominations to grapple with the moral complexities of modern life, and how to live with those of other faiths and none. That, rather than anti-semitism, is its message. But for many, such a retreat into the Middle Ages is only possible on celluloid or, if you can afford it, a mountain in Malibu.