It’s a cold, clear night in mid-December, and on a breezy hilltop in Surrey a crowd has gathered to watch the birth of Christ. It’s a lot colder than Bethlehem, of course, but the setting is uncannily authentic. There’s a barn strewn with hay. There are cattle; there are sheep. There are shepherds warming themselves at small fires dotted around the fields. There’s a young woman in simple white robes, heavily pregnant, clutching her belly; there’s her husband, slightly older, having a bit of trouble coaxing the donkey along the path.

Earlier, the Angel Gabriel put in an appearance from a treetop, calling down to the Virgin Mary below that it was God’s will she should bear His child (she agreed, of course). Later, while she tends her real, live baby in the manger, there will be visits from kings – and then a rather alarming few minutes when the dastardly Herod will arrive on horseback, looking for baby boys to murder in order to rid himself of the upstart newborn king he has been warned about.

It’s all riveting stuff: the story of the night the son of God came down to earth as a helpless, bawling baby is – whether you believe it or not – a cracking tale. And the performers on this hilltop act it out with extraordinary gusto – even more extraordinary given the fact that most of them have nothing much in the way of acting experience. They’re not professionals – they’re amateurs from the surrounding area. They’re all sorts, too: this being Surrey, some are rather well-to-do bankers and estate agents, others are housewives and nurses, yet more are teachers and students. One is a sculptor, one a sailing instructor, another a shopkeeper. For all of them, ordinary life has been put on hold: for a few days during the week before Christmas, they will devote their lives to re-telling the story of Jesus’s birth.

It’s the 18th time they’ve marked this time of year with a “live” nativity play on this windy hillside. And this year, as usual, people will flock to see it from across the south of England. The 6,000 tickets to the ten performances sold out within weeks of going on sale in September: for many, it’s an annual pilgrimage, as much a part of the festive season as turkey or a trip to Santa’s grotto. “We get plenty of people turning up who’ve never set foot in a church,” says Peter Hutley, the man behind it all. “But they’re searching for something – we’re all searching for something. And they’re aware that, behind the tinsel and the endless shopping, there’s a story with real meaning. I like to think that this place, Wintershall, gives them a sense of what that meaning might be.”

From anyone else this might sound like whimsical sentimentality, but Hutley means business. He might be long past retirement (he refuses to give his age, although he does admit that he’s “getting on”), but he’s a man on a mission – and it’s a mission that has turned out to be a great deal more successful than anyone in our godless age might have predicted.

It was back in the late Eighties that Hutley – a successful property magnate – hit on the idea of using part of his fortune and his picturesque estate to perform an annual nativity play. He and his wife, Ann, had become increasingly drawn to faith after visiting Medjugorje in Bosnia, where children were reportedly seeing visions of the Virgin Mary (the couple went on to become Catholics, in the early Nineties). They had been trying to buy a new bit of land and, Hutley remembers, the sale was proving tricky. “A few days before the auction, Ann and I and our four children all walked up to the barn on top of the land we wanted to buy. And I hit on this pact with God: I said to Him, let us buy this land and we’ll use the barn to do something for you. Give it to us, and we’ll perform a nativity play here this Christmas.”

Within weeks Holly Barn was his, and the pact was becoming a reality. That December saw the first play, with the Hutley children and their spouses in most of the leading roles. “Everyone had a job to do,” remembers Mrs Hutley. “The lighting manager was Lulu, my daughter-in-law. She was heavily pregnant at the time, and I remember looking across and seeing her there with a torch between her teeth, reading the script. The first production was done by candlelight: it was pretty basic and only about 40 minutes long.”

Word had got around in the area that the Hutleys were putting on a play. That first year, Hutley remembers, they pushed the cattle out of the barn only a few hours before the performance. There were only ten people in the cast, and the audience – who numbered 50 or so – sat on straw on the floor. It’s all very different today: the barn is kitted out as a theatre, with benches and a stage. There’s a professional lighting and sound system. The play is about an hour and a half long, and as well as the 60 actors there are 20-plus people backstage.

And there’s more. Not only has the nativity grown and become an annual event, it’s spawned other Bible plays, too. As well as the winter extravaganza, Wintershall now plays host to a huge, five-and-a-half-hour production each summer called The Life of Christ, involving an astonishing 270 actors, 60 sheep, 15 horses, two camels and the inevitable donkey. It’s probably the biggest show in Britain. Add to it a smaller show called The Acts of the Apostles performed each October, and somewhere in the region of 22,500 are visiting Wintershall each year to watch a back-to-basics, telling-it-like-it-was version of the events chronicled in the Gospels.

What’s it all about? Well, there’s obviously more than a bit of nostalgia at work, certainly where the nativity is concerned. A generation ago, after all, many of us had more exposure to the Bible story that forms the centrepiece of Christmas than most children do today. Many of the parents who will trek up this hillside over the next few days, children in tow, will do so because they want their offspring to get a real sense, as they themselves did as youngsters, of the magic and mystery of the Bethlehem tale – and as atmosphere goes, a barn filled with animals and hay with a real baby lying in the manger is about as good as it gets.

But it’s not just about nostalgia. There’s a definite sense among the audience of weariness with the commercialism that infuses modern-day festivities. Today’s parents would like Christmas to be about more than shopping and presents, but – since few of them are churchgoers – they’re at a bit of a loss as to how to inject that elusive something more. Wintershall provides people with an opportunity to glimpse something spiritual but, unlike church, it offers that opportunity in an unthreatening way. Tony Blair wasn’t joking when he described how owning up to being a believer these days can make you come across as a bit of a basket-case. Wintershall gives people who want to dip a toe into the water of belief a “safe” place to do so.

For Hutley, of course, there are no such qualms: he has embraced his endeavour with a zeal that knows no bounds. His is a rather eccentric, quaint and remarkably literal belief: the huge, oak-beamed hall of his mansion is dotted around with life-sized plaster statues of the saints, and there are religious memorabilia everywhere. Part of his mission is to deliver a representation of the Gospels that is as close as possible to the original text.

Editor's choice

• The 100 Best Films of the Decade
• 70 facts you didn't know about Marvel
• The 50 Biggest Movies Of 2010