IT WAS a High-Churchman in a kilt who changed A. N. Wilson's life. He was Roderick Gradidge, an architect who worshipped at St Mary's, Bourne Street; and his message to Wilson was uncompromising: "It is utterly egotistical to set one's own personal doubts above 2000 years of human experience." This conversation, at a party, was the start of Wilson's return to the Christian faith after 30 years.

That was a few years ago now; so I was keen to know how his ego and his faith were getting on. "Well, I doubt everything, including myself," he says. "But my religious doubts are not as strong as my doubts about materialism.

"I don't understand many of the doctrines, such as atonement, and I find it hard to reconcile the merciless nature of life to a loving God; but being part of a liturgical Church, where the voice of prayer is never silent and carries you on a stream of tradition, inviting a trust rather than a signing on the dotted line - that's something I rejoice in."

I ask whether he warms to Graham Greene's observation: "The problem is I don't quite believe my unbelief."

"Yes, exactly," Wilson says. "The existence of love, music, and language challenges the bleak and muddled creed of atheism, as does the highly selective approach to facts that many followers of that creed have."

For many people, the image of Wilson is that of a confident, waspish, and reactionary fogey who shoots from the lip in right-wing columns. That is not the man I found.

His recent spat with the historian Richard J. Evans over his review of Wilson's short biography of Hitler seemed a good way to get inside him. How does he feel about criticism? "I get more thin-skinned as life goes by. The art of life is learning to live with your faults - and those of your partner."

So did he feel that he had to put on a pleasing mask as he sat down to write, say, for the Evening Standard? Is there a disappearing act involved in such self-fashioning journalism? "Yes, I think so," he says. "It was a relief in the end to stop writing that piece, so that the persona could be discarded, and the temptation to become self-parodying avoided. It had started to remove me from myself. I think there are fewer masks now. Actually," he adds, somewhat surprisingly, "I don't have many views."

HE SPEAKS gratefully about the church where he and his family worship regularly, and of the parish priest there: and one senses that what he calls his "lapse back into religion" has been personally distilling - more a conversion of outlook than of intellect. He is not romantic about the wider Church he has returned to, however.

He refers to the "institutionalised horror and sheer absurdity" of the Church of England's negative attitude to gay people. "To talk in terms of sin when there is no personal choice about sexual orientation is pure wickedness." He laments the fact that the Church simmers itself down in focusing on small issues, and misses the bigger vision "such as Baron von Hügel, Evelyn Underhill, Charles Williams, and Dorothy Sayers pursued".

In Wilson's mind, religion is too good a thing to leave to the religious, and he quotes William Temple with approval: "I believe in one, holy, catholic, and apostolic Church, and regret it doesn't yet exist."

Nor is Wilson romantic about theologians. He admits to finding a lot of academic theology dry and difficult to understand. "I liked the sound of Radical Orthodoxy," he says, "but, oh dear, it is all so dense. Surely one should be able to understand at least a paragraph?"

One of his 40 books studies the quest for the historical Jesus; so he was also drawn to read the work of N. T. Wright. In this case, however, although he understood it, he disagreed with its conclusions. Reviewing Wright's Simply Jesus (a title that Wilson questions the appropriateness of) in The Times Literary Supplement recently, he concluded that "Wright's whole approach to the subject is based on the fallacy that a mechanism exists, or ever could exist, by which the Jesus of history could ever be recovered. Historically speaking, it was the Jesus of faith, or the Christ of Paul, who came first, and eclipsed the man of Nazareth."

For Wilson, much contemporary theology veers between the incomprehensible on one hand and the unbelievable on the other. He is convinced that we must be reluctant to come to historical conclusions about the stories in the scriptures, and should not commit the error of confusing their truth with their literalism. We must "see the world mythologically, as people have always done, to understand the Christian faith. You don't have to be sophisticated to understand the core reality of God."

Ultimately, Wilson thinks that one can make sense of a religion only by practising it. When a critical friend remonstrated, saying, "but you can't live in a poem," Wilson was startled. "Why not?"

Wilson's literary subjects are diverse and plentiful. Last year alone, he published works on Dante, Hitler, and the Elizabethans. His latest book, The Potter's Hand, is his first novel for five years, and is a novel of ideas. As a biographer and a devotee of Tolstoy - whose detached, cinematic realism he "likes more and more" - he uses fiction to tell the truths of history as he sees them.

The Potter's Hand immerses itself in the thoughts and personalities of the Enlightenment, primarily focusing on the life of the crafts-man and industrialist Josiah Wedgwood. Wilson's father worked as a managing director of Wedgwood, and he admits that this book has happily taken him back to his roots. The early influences of an atheist father, an Anglican mother, and a Roman Catholic education can be seen to "jangle about in me still".

He is a great admirer of the Enlightenment, its scientific quest and innovation. The men of the Lunar Society, for instance, amaze Wilson with their cleverness and the quality of their work. Where Wilson parts company with them is in the optimism of that period about human progress, which, he tells me, "is plainly tragic in retrospect". He quotes Samuel Johnson: "Most schemes of political improvement are very laughable things."

POETS are important to Wilson. He reads Wallace Stevens almost daily. "There is no doubt that discovering his work has changed me," he says, looking down, almost sadly, at the table. "And Yeats I go back to often."

Wilson is more vulnerable, modest, and self-scrutinising than his pen lets on. His study of history has, I suspect, been a study of his own identifications. He appears Elizabethan in his wit and play with the social court, and rather 18th-century in his readiness to condemn the inhumane or superstitious.

He lives with the spiritual doubts that shaped many Victorian minds, but is unafraid to beachcomb the present for values and insights that would restore the justice and beauty of a world that feels too gift-like to allow only for a materialistic interpretation. Wilson has come to recognise that there is such a thing as blind unbelief.

He is engaging and enigmatic; and I sense that, rather like a Wedgwood bowl, the closer you get to him, the more cracks you see. It is telling to observe who you become in someone's presence, and I found myself becoming a better listener - relaxed, able to say anything, readily smiling.

There is always a certain theatricality to the extremely shy - a need to use display to guard oneself. There has certainly been sharpness from his tongue and pen over the years. I wonder, however, whether he is a reserved spirit, for whom writing books rather than columns is an attempt to integrate deep recognitions and expressions of fact, feeling, and thought.

As with all of us, it is his occasional exaggerations that give him away, and which can injure; but, as we parted, I felt that I had interviewed a scholarly, reflective man who is constantly, and often uncomfortably, reorientating himself. After all, as his beloved Stevens asks:

Can one man think one thing and think it long?
Can one man be one thing and be it long?

The Revd Mark Oakley is Canon Treasurer of St Paul's Cathedral.