Away in a manger: How one Surrey man turned a Nativity in his barn into an annual pilgrimage

Jesus's big sister, Hannah, is perplexed. Why, she wants to know, does her mother keep swaddling her baby brother in a big white blanket and lying him in a manger? Who are the strange, exotically dressed men who keep turning up with presents? And why is her family spending so much time hanging out with sheep and donkeys in a draughty barn in the middle of nowhere?

The answer to three-year-old Hannah Clayton's questions is that her family – mother Chrissie, 37, father Andrew, 36, and baby brother Theo, six months – are this year's stars of an extraordinary "live" Nativity play that takes place each December on a hilltop in a rural corner of Surrey.

The Wintershall Nativity Play was born in 1990, when a millionaire called Peter Hutley, who had made his fortune in property, decided to put on a play in a barn on his 1,000-acre estate near Guildford a few days before Christmas, telling the story of Jesus's birth. The Hutleys – Peter and his wife Ann have four children, and today their family also encompasses 15 grandchildren – had no thespian background, but they did have a strong Christian faith, and that year, they'd prayed for the chance to purchase a new piece ' of adjoining land with a picturesque outbuilding called Holly Barn on its highest peak. "I said to God, give us the barn and we'll give something back to you," says Hutley. That December, having successfully bought the land, he was as good as his word. "Peter wrote the play, we roped in various family and friends to play the parts, then we trudged up the hillside to the barn," remembers Ann. "We pushed the animals out, and the people who'd come to watch sat on hay bales.

"It was a terrific atmosphere: the barn was candlelit, the stars were twinkling outside, and baby Jesus was a real, live newborn – our grandson, Nathaniel."

Afterwards, as they all they made their way back down to the house for a cup of something warm and one of Ann's home-made mince pies, everyone was agreed on one thing: seeing the story of Christ's birth performed in a barn had been magical, meaningful and moving. "People loved it, and the following December there was this expectation that we'd do it again," says Hutley. "So we did."

What he couldn't have imagined then was that, two decades on, it would be not only going strong, but would also have grown out of all proportion from its humble beginnings. In 1990, the audience numbered around 30; this year, more than 6,000 will watch the Nativity's 10 performances, with people travelling from across the south-east of England and beyond. What's more, Hutley's idea of a live, traditional retelling of the story at the heart of Christmas has been taken up in other areas, too, including Hampshire and Scotland – and in the new year he's due to visit Perth in Australia, where there's interest in doing something similar.

Nor has it been limited to Christmas: following the success of his Nativity, Hutley branched out and wrote a play based on the story of the Passion and Christ's death, and also an epic, six-hour-long play encompassing Jesus's entire life: these are performed at Wintershall in April and July respectively, and on Good Friday this year the Passion play "toured" to Trafalgar Square in London, where it is due to be shown again in 2011. All of which means that, these days, upwards of 40,000 people a year are experiencing one of Hutley's Gospel extravaganzas. "I hope they'll run and run," he says. "After all, the story that sparked them is 2,000 years old, and it's still the greatest story ever told."

Hutley writes all the scripts himself, making subtle changes each year, and he's as faithful as he can be to the Gospel text. The Wintershall plays aren't modern or "new takes" on the original: what you read in the Bible is what you see on the stage (give or take the odd tweak – in the Nativity play, for example, King Herod is rehabilitated in the final scene and ends the show holding hands with a couple of the children he was earlier intent on slaying. "We can't make it too bleak," explains Hutley).

Just as the audience has grown, so too has the cast, which has mushroomed to around 70. I joined them at Holly Barn on a freezing December afternoon as they went through one of their final rehearsals for this year's show. Just as with the original play, all the actors are amateurs, most of them drawn from the villages around Wintershall; they come from a variety of backgrounds, and include (this being Surrey) a heavy sprinkling of financial advisers, solicitors and accountants as well as nurses, housewives and plumbers. (One year, apparently, the actor who took the part of Joseph was actually a real-life carpenter.)

There's a strong camaraderie among the actors – you get the sense you're among people who've known one another for years – as indeed most of them have. One of the interesting aspects of the play is that the family at the centre of the show – Mary, Joseph and the baby – are usually recruited as a real-life job-lot, which means they're often "outsiders", as is the case with the Claytons this year. "It was the baby they were after," jokes Chrissie, standing as close as ' possible to the heater in the icily cold green room between scenes, as she explains what got her the starring role. "I'm a GP; the last time I did any acting was at school. But my neighbour is involved in the technical side of the play, and he told me they were on the lookout for an infant to play Jesus, and he thought Theo would be perfect.

"We said yes without realising what was going to be involved: we thought they'd just need the baby, but then we met Mr Hutley and he explained that he wanted me to play Mary, and Andrew – who's a solicitor – to play Joseph. I was a bit shocked – but he was very persuasive. I think he sits outside maternity units looking for people like us!"

The Claytons are Anglicans, although Hutley says not all the cast are Christians or even believers – one year, Mary and Joseph were played by a Jewish couple (they had, of course, the all-important baby). He always, he says, works hard to find a real-life family to play the central roles – and, watching the rehearsal, you can understand why that matters more than acting experience. Throughout the 75-minute-long performance, whatever else is going on, it's clear that the person Chrissie and Andrew are both most concerned about is baby Theo. When Chrissie holds him out so that the shepherds or the magi can see him, she does so with real-life pride on her face; when she hands her bundle over to Simeon, the old man in the temple who has waited all his life to meet the Son of God, you can feel the trepidation with which she parts with her precious newborn.

What's more, when Chrissie offers thanks for the gift of a son, you know absolutely that she's doing it from the heart, because little Theo, six months old, is something of a miracle baby himself. "He was born at 28 weeks after my waters broke early; very sadly his twin brother, Reuben, died at birth," says Chrissie. "Theo weighed 2lbs 2oz when he was born, and he was in hospital for more than three months. So yes, you could say that Andrew and I see this play as a way of thanking God for bringing him – and us – through an incredibly difficult time."

Ashley Herman, the play's director, is one of the few "professionals" involved – he works in theatre marketing and production. But, he says, though the people he puts through their paces for the Nativity certainly aren't paid-up members of Equity, they're as professional as anyone he's ever worked with. "I expect exactly the same from them as I would from a cast in the West End: they have to turn up on time, and I work them really hard."

Ambridge it isn't, he says (though he can see why some people might compare it to the annual panto on The Archers, with the cast all recruited from the village). So what does he attribute its success to? "The audience get an experience which is great value, and hugely enjoyable. In a nutshell, they get a bang for their buck. This isn't a po-faced polemic: what I tell these actors is that they are on ' a journey through this story, and that if they live in that journey, they will take the audience on it with them.

What's more, he says, the material is second to none. "The more you work on the Nativity story, the more you realise what a rich source of theatre it is. All of human life is there: it's got an incredible range of characters, and a huge amount of emotion and impact."

Also hugely refreshing to many who gather for the play each year is the fact that Wintershall is – at a time of year when every carol seems to be accompanied by the sound of a ringing cash-till – delightfully un-commercial. Ticket prices, at £15 and £7.50 for children, are cheaper than almost any other Christmas show – and unlike most of the events you're likely to find yourself at over the festive period, there's no gift shop and no one is trying to get you to dip your hands ever deeper into your pockets.

It's also, for children especially, hugely exciting: the play opens outside, with the actors gathered around roaring fires and the crowd parts to make a way for Joseph, who is leading a donkey (played by Chester, another old hand) carrying Mary on his back. More "wow" moments follow once the audience are seated in the barn – the arrival of King Herod on (real) horseback is wonderfully dramatic, and a scene in which his men go seeking babies to murder, following Herod's orders to kill all boys under two, is more than a little scary.

The money the show makes is ploughed into costs – the once-humble Holly Barn has now been kitted out to resemble a rustic theatre, with tiered pine benches rising to the back of the hall so everyone gets a decent view, professional lighting, and a state-of-the-art sound system. The Hutleys, says Nick Fiddian-Green, their son-in-law and – of course – an actor in the play, this year appearing as Balthazar, have devoted the past two decades of their lives to their Bible shows. Ann remembers that, one year, Peter gave her a choice between having a new kitchen, or getting better lighting for the barn. "I chose the kitchen, but Peter then said he'd already decided we were having the lighting," she says.

Peter Hutley is also an indefatigable fundraiser, directing his efforts especially at paying for a new heart and stroke unit at his local hospital, the Royal Surrey. To this end, he opens up the farm each summer for top-name concerts – in the past, they've featured stars such as Eric Clapton, Ringo Starr and Bob Geldof. "We see them socially occasionally," he says. Do they ever come to the Nativity play? He thinks not, but says that if they ever wanted to, they would, of course, be very welcome.

What's extraordinary about the Hutleys is that they find the energy to go on, year after year, rolling out the show, leading from the front, and micro-managing its production. Doesn't Peter ever dream of a quiet retirement? "Not really," he says. "God has been good to me. I want to share what I've got with others, and I want to share the Gospel stories, at a time when they're often not to the fore, with people who I think do yearn to know them, and to understand them."

Back at Holly Barn, the rehearsal is a wrap: and Chrissie and Andrew Clayton have wound themselves out of their robes and back into their jeans and jumpers. "You're normal again!" says Hannah. "I don't think any of us is normal," says one of the shepherds brightly. "Who in their right mind would spend every Sunday in December in a freezing barn?

"But then again," he says, musingly. "Ask me where I would rather be, and I'm not sure there is anywhere else. Christmas shopping? This beats that hands-down. Watching telly? Why would I want to do that?

"Whether you believe this story or not, it's great theatre. And it's got us all hooked." n

For more about this year's Nativity,which continues to 21 December, visit wintershall-estate.com