"I feel sorry for the church next door, waiting for their three people to trickle in," says Nick Julius, glancing at the small adjacent hall that will shortly be hosting its own gathering.

There are still 40 minutes before the Sunday Assembly, an atheist service run by two standup comedians, is due to begin, but a queue of eager congregants is already forming outside a grand but crumbling former church in Islington, north London, hands shoved deep into pockets against the cold.

Julius arrived an hour early, just to be sure of a place at the service, which is described by its organisers as "a godless congregation that meets … to hear great talks, sing songs and generally celebrate life". But why? "I came last time and really enjoyed it. It's got all the good things about church without the terrible dogma. I like the sense of community – and who doesn't enjoy a singsong?"

This is only the second time Sanderson Jones and Pippa Evans have hosted the monthly event (motto: live better, help often, wonder more), and they admit to being a little overwhelmed by the enthusiasm with which the event has already been greeted.

More than 200 people came to the first event; today there are perhaps 300, with several dozen more carrying on a parallel discussion in a local pub. Inside the nave of the deconsecrated church, volunteers have been bunching chairs closer together, adding extra benches and children's seats in every scrap of space. It is not a problem most vicars struggle with on a Sunday morning.

ones, a tall, bounding figure with a hairstyle and beard verging on the messianic, says the idea emerged from his comedy, where he encouraged those coming to his gigs to get to know one another, and they in turn pressed him for ways to stay in touch and even build small groups. There was clearly a thirst for community, he decided, and perhaps others felt, as he did, that words such as awe and transcendence shouldn't be the preserve only of religious people.