Why are so many teenagers reading a novel based on a 17th-century poem about Satan? Is there a place in the RE classroom for a best-selling author who says, “There is no God”?

The final volume in Philip Pullman’s trilogy His Dark Materials was the first children’s novel to win the overall Whitbread Prize. It is a mind-stretching story, exciting and moving. It is also profoundly rebellious.

Few things distress fiction writers more than having their work forced on an unwilling class, with topics dragged out to fill tick-boxes on a curriculum chart. But when a book creates such a buzz, we may be failing pupils if we do not share in it. Fiction, especially fantasy, is a “What if?” It can prompt questions even the author may not have intended.

Children’s fantasy novels began with Charles Kingsley’s The Water Babies. In the guise of an underwater adventure, it is a startling story about God. This Victorian clergyman shows us the divinity as a barefoot Irish peasant, as a pantomime dame with hooked nose and green spectacles, as a voluptuous mother, and as the calm creator Mother Carey. Another Victorian minister, George MacDonald, also makes his divinities female, with great grandmother in the Princess books and the Wise Woman in the book of that name.

Why do these Christian writers depart from the largely male representation of God in the Bible? There is a rich vein to mine in the representations of the divine in children’s fantasy. Nothing could be more masculine than CS Lewis’s golden lion, Aslan. Kingsley and MacDonald’s divinities are approached through the mystery of water, forests, tunnels, staircases. We first see Aslan as a king in a battle-camp in the blaze of day. How do children feel about this approach to God? What situations, in nature or buildings, give them that shiver-in-the-spine, religious awe? And what is it about Aslan, both powerful and playful, which is so appealing?

After Lewis, there is more reticence about portraying God as a character in the novel. Madeleine L’Engle has a wonderfully humorous trio of Mrs Whatsit, Mrs Who and Mrs Which, and a glorious cherubim, but they are agents of good, not divinity itself. So are Tolkien’s Gandalf, and Alan Garner’s Cadellin Silverbrow.

These last two have brothers - mirror-images of themselves, who side with evil. Is this how children feel about their conflicting selves? Ambivalence is seen most tellingly in Ursula Le Guin’s A Wizard of Earthsea, where Ged turns and embraces the pursuing Shadow with his own name. Can we relate this oneness of dark-with-light to the influence of Taoism on Le Guin? Must fantasy be a conflict between absolute good and evil?

Good shines more vividly than evil in the Victorians’ books. But in the late 20th century, horror stalks the pages. Children revel in the gruesome. Why the difference? Is it that earlier generations had a real fear of evil, but that today it has become a game? Or are children telling us they have dark fears which need to be addressed in a safe environment?

In his Deptford Mice sequence, Robin Jarvis bucks the trend against portraying divinity. In contrast to Lewis’s golden Lion, we meet the Green Mouse, an image of vulnerability which Aslan only achieves in his death scene. Aslan saves others. The Green Mouse is saved by his followers. Are we in God’s hands or has he put himself in ours?

The move is away from a controlling deity, shifting power to the child. Even as a baby, Harry Potter thwarts the onslaught of evil. Philip Pullman kills off God. His parallel world is ruled by a Church which worships “the Authority”. Do our pupils see the Christian Church as seeking to dominate them? Are there other ways of “being Church”? Pullman has based his books, not on the Fall in Genesis, but on John Milton’s Paradise Lost. The inspiration is a Hebrew tradition of war between the angels, led by the rebel Satan. Pullman’s Lord Asriel makes war on the Authority, whom he equates with cruelty and death. Is it this spirit of rebellion which makes such an appeal to teenagers? Is Pullman’s view of God paralleled in the Gospels or has Christ’s Church itself distorted the Gospel of love?

Pullman uses Adam and Eve’s temptation to knowledge as a metaphor for growing up. His fictional Church separates children from their daemon animal-form selves, to protect them from Dust, which it equates with original sin. This separation either renders them passively obedient or kills them. The former nun Mary, who has rejected her Christian faith, shows the children that Dust is really the source of wisdom and life. Does religion stop people growing up? Why did Jesus urge his followers to become like little children?

Lyra herself undergoes the agonies of separation and dying, to find a friend she unwittingly led to his death. In doing so, she and Will free all the dead from a miserable underworld. There is no joy in Pullman’s eternity. The dead rejoice as they disintegrate into atoms of the living world. How do teenagers react to Pullman’s belief that we must make heaven ourselves, here and now, because “there ain’t no elsewhere”? What do the Gospels say about heaven on earth?

Pullman’s Authority, himself, dissolves into nothingness. Old, pathetic, running away, he was only an angel playing a confidence trick. Is this the crumbling of a false image of God? Or do children see this as the death of any God?

Has Pullman played fair? Could he substantiate the implied parallel between his “Authority” and Mary’s loss of faith in the Trinity of Father, Son and Spirit?

Mary left her convent to live fully in the physical world. Lyra and Will movingly renounce their physical love for each other to safeguard the integrity of their different worlds. They suffer death to free others. Pullman set out to rewrite Paradise Lost. Has he unwittingly retold the story of Christ?