Inside the Sunday Assembly. Credit:Peter Rae Eventually, though, he stopped believing in any of it. "It was a long process and painful," he says. "There was depression and the sense I was losing all the things that were important to me." There was no single epiphany in his "spiritual transformation", but a multitude of small realisations over many years. "It came to a point where I just turned around and didn't believe in God because the evidence was insufficient," he says. "There was no God. There was no God calling me. It seemed to me the whole edifice that I had built for myself was founded on nothing." He pauses and sighs. "There are times now when I think, 'Oh, why didn't I just toss it in from the beginning?' " The ranks of Australians saying they have "no religion" - a loose, catch-all term that includes atheists, agnostics, freethinkers, socialists, rationalists and humanists - have grown over the past century from one in 250 people to one in five. In 1911, 10,000 people - 0.4 per cent of the population - described themselves as having "No religion" in the Census. In 2011, the same group numbered 4.8 million or 22 per cent - more than any other group, bar Catholics (25 per cent). Ashcroft left the church and lay in bed on Sunday mornings. "I looked around and thought, 'What do people do on Sundays?' " he says. For a time, he attended different churches, hoping to find something of what he'd lost. "I was wondering if there was some way I could be a minister without being a Christian. I wanted all the other things - the social aspect, the sense of community and common purpose - but not the religion."

Former Baptist minister, and now atheist Chris Ashcroft at the service. Credit:Peter Rae In November last year, a friend invited him to the first gathering in Sydney of the Sunday Assembly, a global atheist church that adopts secular versions of religious rituals. Indeed, the first time I meet Ashcroft is on a sunny morning in late September at a service in Redfern Town Hall, in Sydney. He greets me inside a large rented room with bad acoustics, featuring an honour roll to the war dead. We're all wearing name tags. I'm introduced to "Gavin", who tells me how he went from "extreme atheist" to agnostic with the aid of mathematical formulae. The Sunday Assembly - which prefers to be known as a congregation without God - welcomes all comers. Its gatherings are based on the rituals of a conventional religious service, with one critical difference: there's no worship. A congregation of about 40 people stand for songs, sit for readings and bow their heads in reflection, a structure that reminds me of the Catholic masses I attended every weekend as a child. A child's naming ceremony at the Sunday Assembly. Credit:Paul Jeffers The songs, which have been chosen to match the theme of belonging, include Christine Anu's My Island Home and Randy Newman's Toy Story theme, You've Got a Friend in Me. There's no kneeling. Ashcroft gives a "sermon" about his work in child protection and the need everyone has to "belong". Donations to cover the cost of hiring the hall are collected in brown paper bags.

There are tea and cakes after each monthly service. "It is a very middle-class thing," Ashcroft says. "You don't get a lot of blue-collar or homeless types." Strong athiest Catherine Deveny speaks during the Sunday Assembly. Credit:Paul Jeffers The sunday assembly was founded by english stand-up comedians Sanderson Jones and Pippa Evans in a deconsecrated chapel in Islington, North London, in January 2013. It now numbers 64 congregations globally, including six in Australia. Melbourne co-founder Kate Murray, 32, calls herself an atheist - with reservations. She tries to explain. "An atheist culture has emerged that is represented by a loud, extreme minority. It's very anti-religious and has elements of hero worship of people like [strident atheist] Richard Dawkins." Some in this minority think the Sunday Assembly is doing the cause no good. "As in," she adds, "we shouldn't have anything to do with religion and we shouldn't be gathering on Sundays." Murray went to a Catholic school and tried to live by the rules laid down in the Bible, but its contradictions rankled: "When you are reading the Bible as a story, it's fine, but once you try to see those things in the real world you realise it's not applicable." She says she stopped believing in God, but not in church rituals. "The thing church does that the pub and general meet-ups don't, is it addresses the human condition. It's a place to go where you think about how you can be a better person."

About 80 members of Melbourne's Sunday Assembly gathered in October to celebrate a secular-style baptism, or "welcoming to the world", of Murray's 10-week-old daughter, Winnie. The ceremony included two "odd parents" pouring coloured sand into an old vodka bottle shaped like a skull - a reminder of mortality. I ask her what she hopes Winnie will believe in one day. "If she became Christian or Hindu, I would totally understand that, because I went through that as well," she says. "I would be surprised if she calls herself an atheist. People who use the term more often come from religious backgrounds, whereas people who haven't come from God don't need to wear that label at all." Michael Thackray's dad cooked pancakes for his family on Saturdays before they read the Bible around the kitchen table. Sundays they would spend at church, where Thackray's dad, Richard - a former rugby league player known as "the Axe" - was the Baptist minister. There was church group on Fridays, Bible studies on Wednesday. "Our whole life was based around church," says Thackray, 33. We meet by a lake at Sydney's Macquarie University, where he is studying psychology. Thackray is lean with faded jeans, black hair and long, fine fingers. His parents met at Bible college and started a family in Mount Druitt in Sydney's outer west. He was the third of four children. "I look back on my childhood and it wasn't happy," he says. "We were brought up believing you are imperfect and you are a sinner and the only reason you aren't going to Hell is that God has redeemed you. You are brought up with the idea you are worthless outside of God. Even now, I struggle with self-esteem issues." His father paid for him to go to Bible college at Loftus, in Sydney's south, for a year, and it was here Thackray's faith began to unravel. He became disillusioned by the narrow-mindedness of those he met and began to seriously examine his belief. "The more research I did, the more it fell apart," he says. "It just starts crumbling away at the edges. I woke up one day saying, 'I'm actually not in a position where I could call myself a Christian.' " I first meet Thackray at Sydney's Sunday Assembly after hearing him read Max Ehrmann's Desiderata, which includes the line: "Be at peace with God, whatever you conceive him to be." "That makes sense to me because I perceive God to be, if anything, an idea," he says. He prefers, however, the line: "You have a right to be here." "It gives people a sense of belonging," he says. "You can take comfort in the fact you're part of the universe."