What happens at an atheist church?

An "atheist church" in North London is proving a big hit with non-believers. Does it feel a bit like a new religion?

Not many sermons include the message that we are all going to die and there is no afterlife.

But the Sunday Assembly is no ordinary church service.

Launched last month, as a gathering for non-believers, it is, in the words of master of ceremonies Sanderson Jones, "part foot-stomping show, part atheist church, all celebration of life".

A congregation of more than 300 crowded into the shell of a deconsecrated church to join the celebration on Sunday morning.

Instead of hymns, the non-faithful get to their feet to sing along to Stevie Wonder and Queen songs.

There is a reading from Alice in Wonderland and a power-point presentation from a particle physicist, Dr Harry Cliff, who explains the origins of dark matter theory.

It feels like a stand-up comedy show. Jones and co-founder Pippa Evans trade banter and whip the crowd up like the veterans of the stand-up circuit that they are.

But there are more serious moments.

The theme of the morning is "wonder" - a reaction, explains Jones, to criticism that atheists lack a sense of it.

So we bow our heads for two minutes of contemplation about the miracle of life and, in his closing sermon, Jones speaks about how the death of his mother influenced his own spiritual journey and determination to get the most out of every second, aware that life is all too brief and nothing comes after it.

The audience - overwhelmingly young, white and middle class - appear excited to be part of something new and speak of the void they felt on a Sunday morning when they decided to abandon their Christian faith. Few actively identify themselves as atheists.

"It's a nice excuse to get together and have a bit of a community spirit but without the religion aspect," says Jess Bonham, a photographer.

"It's not a church, it's a congregation of unreligious people."

Another attendee, Gintare Karalyte, says: "I think people need that sense of connectedness because everyone is so singular right now, and to be part of something, and to feel like you are part of something. That's what people are craving in the world."

The number of people declaring themselves to be of "no religion" in England and Wales has increased by more than six million since 2001 to 14.1 million, according to the latest census. That makes England and Wales two of the most secular nations in the Western world.

Figures such as writer Richard Dawkins and comedian Ricky Gervais have made it fashionable to be more assertive about having a lack of religious faith and to think about what it means to be an atheist.

And writer Alain De Botton has unveiled a Manifesto for Atheists, listing 10 virtues - or as the press has already dubbed them "commandments" - for the faithless.

De Botton says he wants to promote overlooked virtues such as resilience and humour. He came up with the idea in response to a growing sense that being virtuous had become "a strange and depressing notion", which seems to chime with the Sunday Assembly's own mantra "live better, help often, wonder more".

He argues for a new breed of secular therapists to take the place of the priesthood and believes atheism should have its own churches, but adds: "It should never be called that, because 'atheism' isn't an ideology around which anyone could gather. Far better to call it something like cultural humanism."

There is a concern among some non-believers that atheism is developing into a religion in its own right, with its own code of ethics and self-appointed high priests.

Jones insists he is not trying to found a new religion, but some members of his congregation disagree.

"It will become an organised religion. It's inevitable. A belief system will set in. There will be a structure, an ethical outlook on life," says architect Robbie Harris.

He believes Evans and Jones have "a great responsibility" if the Sunday Assembly "continues to be as successful as it is now".

"There is a difficulty that it might become cultish and it might become about one person. You could set yourself up as a charismatic preacher, that's the danger."

Fellow congregation member Sarah Aspinall says: "I think Sanderson should step back and see himself as a mediator and an enabler, which I think he is obviously good at, and just bring people up to speak or read."

Jones says it is very early days and future assemblies will be less about him and more about the experiences of congregation members. He bridles at the suggestion he is starting a cult.

"I don't think I'm a charismatic preacher. I just get very excited about things and want to share that with people."

He says he has been overwhelmed by the public reaction to the Sunday Assembly and is exploring the possibility of setting up similar gatherings around the country.

"I wanted to do this because I thought it would be a wonderful thing," he explains.

The Sunday Assembly certainly did better business than at the evangelical St Jude and St Paul's Church next door, where about 30 believers gathered to sing gospel songs and listen to Bible readings.

But Bishop Harrison, a Christian preacher for 30 years, says he does not see his new neighbours as a threat, confidently predicting that their spiritual journey will eventually lead them to God.

"They have got to start from somewhere," he says.