"We've been living through the last twilight of the Enlightenment," the writer Philip Pullman tells me. "There was a period for a couple of hundred years when we were free to say what we wanted. But that age is drawing to a close, because people are now far more ready to take offence. Christians in this country today say they aren't being respected. But the idea of demanding respect seems to me a profoundly un-Jesus-like thing to do."
Pullman is talking to me in a café close to Broadcasting House in London, where he has just done an interview. As we sit down, Mark Thompson, the director general of the BBC, enters the (rather more expensive) restaurant next door. Pullman, an avuncular 63-year-old whose face usually suggests a kind of amused curiosity, shoots me a vaguely disapproving look.
One imagines he'd have pulled a similar face when, in 2002, the conservative commentator Peter Hitchens used his column in the Mail on Sunday to anoint Pullman "the most dangerous author in Britain". The Amber Spyglass, the final instalment of his trilogy of children's novels His Dark Materials, had just won the Whitbread Book of the Year Award. For Hitchens, these books, set in an alternate universe administered by a gruesomely authoritarian church, were just "moral propaganda".
Yet not all Anglicans are so quick to take offence at Pullman's work. In 2004, the Archbishop of Canterbury, Rowan Williams, joined him in discussion at the National Theatre, where Nicholas Wright's stage adaptation of His Dark Materials was playing to packed houses. Williams had previously hailed the production as a "near-miraculous triumph", but also insisted that His Dark Materials was much more than simple "anti-Christian polemic". This was the archbishop's way of acknowledging that Pullman's atheism is shaped more by a preoccupation with the depredations of arbitrary ecclesiastical power than by theism's claims about the existence of a supernatural being. As he put it in his conversation with Pullman, His Dark Materials is "entirely about control".
The church depicted in the trilogy appears wholly lacking in redemption. What, wondered Williams, had happened to Jesus? Pullman pointed out that he is mentioned once in His Dark Materials, "in the context of this notion of wisdom that works secretly and quietly, not in the great courts and palaces of the earth, but among ordinary people". He promised he would return to the "teaching of Jesus" in his next book. For some time, Pullman's fans had assumed that this would be a novel, tentatively entitled The Book of Dust.
That book has yet to materialise, but now he has got round to paying closer attention to the figure of Jesus in a new work of fiction, The Good Man Jesus and the Scoundrel Christ. The book strenuously advertises its status as fable: the legend "THIS IS A STORY" is embossed in gold letters on the back of the jacket. And it begins with the proposition that Mary gave birth to twins - a charismatic social teacher and visionary named Jesus, and his tormented and self-conscious brother, Christ, architect of the church that would eventually be built in his sibling's name.
The whole thing is a provocation, naturally. But Pullman is sanguine about what he dismisses as the "pre-emptive offence" some have already taken against him and the work. "Admittedly, the title is provocative, but then the function of a book title is really a double one: it has to say something about what the book's about and it has to attract attention. I'm not ashamed of that. But people have taken offence and have written to me telling me that my life is an affront to God and that I'm going to hell."
Pullman has good reason to be relaxed: threats of eternal damnation, to which he has been exposed ever since the publication in 1995 of Northern Lights, the first in the His Dark Materials series, haven't dented his sales. The trilogy has sold more than 15 million copies.
What his detractors miss is the extent of Pullman's imaginative sympathy with certain aspects of religious observance. This stems, in part, from his rootedness in the language and liturgy of the Anglican Church (his grandfather was a clergyman in Norfolk). I ask him if he is still happy to describe himself, as he once did, as a "Church of England atheist".
“Entirely happy. The phrase 'cultural Christian' is sometimes used, and it does describe someone who has the liturgy of the Church in the very neurons of the brain; the connective tissue of their mind is saturated with the words and language of the Book of Common Prayer. Many thousands - millions - of men and women must have been absorbed and intoxicated by the sound of that language."
Those millions have also been inspired, if Pullman is right, by the example of Jesus's teaching. His new book is an attempt to save what he has called the "genius of Jesus" - his genius as both storyteller and moral exemplar - from the "Christ of speculation", the risen Christ who appears in the Epistles of St Paul. "If you look at the Epistles, the word 'Christ' appears more than 150 times, the word 'Jesus' only about 30. It's quite clear that his preoccupation is with the Christ who has ascended into Heaven. And it's total fantasy, total fiction."
It is a fantasy or fiction that has had the most far-reaching consequences. In one of the new book's most important scenes, we see Jesus in the Garden of Gethsemane conjuring a nightmarishly bureaucratic vision of the church his brother wants to bring into being. Pullman says Jesus's soliloquy is the "prayer of a man who is losing his faith. Jesus says: 'As soon as men who believe they are doing God's will get hold of power . . . the devil enters into them.' It's because they believe they have a power that nobody can argue with."
“Power that nobody can argue with" - that is the essence of what Pullman calls "theocratic absolutism", a notion which, for him, refers to the arbitrary domination of one human being over another, and which needn't entail belief in the supernatural. "The Soviet Union acted like a theocracy," he points out. "There was a holy text (the works of Marx) and a priesthood (the Communist Party) that had rights and privileges that were denied to the laity."
The fate of "rights and privileges" in this country is something that has exercised Pullman a good deal recently. In February last year, he addressed the Convention on Modern Liberty. Britain, he declared, was sleepwalking towards authoritarianism. "It's not very good," he says of the government's record on civil liberties. "I'm not suggesting there's been a sort of evil plan cooked up by [Peter] Mandelson in a secret bunker. But by their fruits shall we know them. Civil liberties are under threat."
Does he despair of the political class as a whole? "No. I always vote. Voting is a privilege. For much of my life, I lived in a safe Tory seat, but I still voted. Oxford in 1997 was fairly marginal and I wanted very much to get rid of John Patten, and I wanted a Labour government. But there was no point in voting Labour at that stage, so I had to vote Liberal Democrat. Our stupid voting system requires you to make calculations like that all the time. It's preposterous and we must change it."
For that reason, he is hoping for a hung parliament. "My fingers are firmly crossed. I very much hope we get one." That would be a small victory for progress. But Pullman is altogether less optimistic about the outcome of the larger, more momentous struggles that confront us. "The game for free inquiry is clearly not up just yet," he says. "We're able to talk, you're able to publish the magazine. But it's been a very small bubble of time in which all that has been possible. Just 400 years ago, we wouldn't have been able to talk like this. And everything changes, eventually comes to an end. It wouldn't surprise me if we found ourselves in a more repressive, less tolerant, more totalitarian era."
Jonathan Derbyshire is the culture editor of the New Statesman
Philip Pullman's "The Good Man Jesus and the Scoundrel Christ" is published by Canongate (£14.99)