The metropolitan faith-boost is the brainchild of Peter Hutley, property-millionaire turned 21st century mystery play writer, who says he was walking through the country’s most famous square recently when he thought: ‘Why on earth does no-one perform a Lenten Passion Play here?’

Back home on his farm in Wintershall, Surrey, the idea germinated. ‘I thought, it’s one of the best-known public spaces in the world, so why hasn’t anyone thought of bearing witness to the central events of Christianity there? I was struck by how inspiring it could be, and how significant a place it was in which to proclaim the central message of Christianity out loud for all of London – and beyond it, all of Britain – to hear.’

Hutley is no stranger to having ‘big ideas’ for God. Nearly 20 years ago he and his wife Ann, both converts to Catholicism after visiting the shrine at Medjugorje in Bosnia, were trying to buy a piece of land next to their farm off the A3. Their chances of securing the sale weren’t going well, and a few days before the auction the Hutleys and their four children all trudged up to the barn on the top of the hill they were hoping to acquire. ‘We all wanted this land so much, and I suddenly had this idea. I said to God: let us buy it, and we’ll use the barn to put on plays for you.’

The auction, needless to say, went their way: and a few weeks later, delighted with their new land, the Hutley clan was in full flow planning their first gospel play in Holly Barn. The theme was the nativity: each member of the family had a role, and the sheep and cattle played themselves. The audience, who trudged up the hillside from the village below, sat on straw on the floor.

It was a hit: and the Wintershall nativity play has been a bigger hit each year since. 2009 saw its 20th year in production: the Hutley family are still heavily involved, but these days there are several performances, the audiences number thousands in total, the play is 90 minutes long, there’s a professional lighting and sound system, and as well as 60 on-stage actors there are at least 20 backstage workers.

And from the nativity, more plays were spawned. Wintershall now plays host to a marathon, six-hour production each summer called The Life of Christ, involving 270 actors, 60 sheep, 15 horses, two camels and a donkey; there’s also a smaller show each October taken from The Acts of the Apostles.

What’s most astonishing about the Wintershall plays is that none of those who take part, from Peter Hutley himself who writes the scripts to the newborn baby who plays Jesus, is a professional. They’re all amateurs, drawn from all walks of life – one year, the parts of Mary and Joseph were played (significantly enough) by a Jewish couple. Other actors have included a sculptor, a sailing instructor and a shopkeeper: last Christmas’s Joseph, significantly, was a carpenter. Usually the Christ-child in the nativity play is the real-life baby of the couple playing Mary and Joseph, which adds to the play’s charm although it gives the parents some headaches about how to keep their tiny child warm in a chilly barn.

Beyond Wintershall, Hutley has written a Passion Play that’s performed each year in Guildford, bringing the busy town centre to a stop each Holy Week as people of all faiths and none pause for a few minutes to watch the events of 2,000 years ago that were to change the world forever. And it’s the feedback he’s had from Guildford, where the play has become a regular event on the town’s calendar, that has brought him here to Trafalgar Square. ‘Many of the people who come to Wintershall to see our plays, or who stop to watch the Passion Play in Guildford, never set foot inside a church,’ he says. ‘But they’re searching for something – we’re all searching for something. And when they see the Passion Play enacted, they can see and they can feel that this is a story with real meaning.’

Although there were some worries from local shopowners about the play in Guildford affecting trade adversely, the opposite turned out to be the case – more visitors, not fewer, have flocked into the town centre to see the play. Although passion plays, or mystery plays as they are also sometimes called, were started back in the Middle Ages as a way to communicate gospel stories in an age before the printed word, Hutley believes that it still has a place in our computerised, TV-saturated world of today. ‘We all need to pause, and listen, and think sometimes,’ he says. ‘Watching a Passion Play is a moment to do that, and Trafalgar Square will be the perfect place to encourage large numbers of people to pause and to think.’

For Trafalgar Square, Hutley is penning a brand new script – one which will take in all the health and safety requirements of the capital’s mandarins as well as seeking to communicate the central gospel themes. He hopes to be able to have horses in the play – and for Christ’s entry into Jerusalem, a donkey of course is de rigeur. There has, he says, been tentative support so far from many quarters in the Greater London Authority, plus less surprising but extremely welcome support from Archbishop Vincent Nichols of Westminster.

One of the most interesting moments of the Trafalgar Square play, Hutley hopes, will be that moment when Christ arrives into the square on his donkey, palm leaves strewn below its hoofs. ‘I think it’s important that the audience don’t think of Jesus as just a poor man who was crucified, because it wasn’t like that,’ he explains. ‘The truth is that he made this triumphal arrival into the city, and people were cheering him and welcoming him – the same people of course who would turn on him and call for him to be killed.

‘What I hope will be powerful about performing this play in Trafalgar Square is that people will be part of the crowd, and that they will join in and start to understand in a new way the events of all those years ago. There won’t be taped-off areas in this play: it’s not about us and them, it’s about us. The public will be part of it…we’ll all be part of it…’