Bob Ayres can't resist a good cathedral. He's done all the biggies - Canterbury, St. Paul's, Salisbury, Wells - and ticked off dozens of others.
But Mr. Ayres is no churchgoer. "I'm a bit of a heathen really," the Londoner chuckles. "I don't go to church. I just like visiting them for the architecture."
It's the same for his brother Keith. "My wife goes to church but I don't," he admits after nosing around the splendid interiors of St. Bride's church in London. "In all the churches I've visited, I've found an atmosphere of peace and serenity," he adds.
The Ayres typify a slightly incongruous trend in Britain: In a country where regular worship is in decline, and faith has moved to the margins, church tourism is becoming hugely popular.
Official figures show that almost nine million people visited 35 places of Christian worship last year. Visits to all churches are estimated at more than 20 million. That compares to barely 4 million regular Christian worshippers.
Last year, for the first time, more than 1 million people visited the 300-odd British churches that are no longer used for worship but are preserved as historic monuments, according to the Churches Conservation Trust, a charity that looks after such churches. This is almost double the number from four years ago.
The Trust's Helen Lang attributes the increase to a surge of interest in heritage and the "peace and tranquility our beautiful churches offer people as an antidote to the ... strains of modern living."
One recent survey found that 80 percent of people professing no religious conviction visited a church last year. Many churches say they have more visitors than regular worshippers.
St. Bride's, for example, pulls in about 100 worshippers each Sunday, but weekday recitals, a compelling centuries-old narrative, and a popular location ensure that dozens of tourists pass through its portals every day.
The tourist traffic stands in marked contrast to church worship in Britain. Barely 7 percent of the population here regularly attend church - compared to 25 percent of Americans who do. Nearly 50 percent of the British population regularly attended church 100 years ago.
The decline has closed hundreds of churches. Some 30 churches are shut down in Britain each year.
"The overall decline is broad, and some of the projections for denominations suggest some won't be sustainable in 15 to 20 years," says Jonathan Bartley, director of Ekklesia, a think tank based in London.
He says Protestant denominations like the Methodists, the Salvation Army, and the United Reform Church will wither unless the decline is averted.
Religious observers offer several theories to explain the decline in church-going and the rise in church-visiting.
The first uses a lower-tide-sinks-all-boats model. Grace Davie, chair of the sociology of religion at Exeter University, notes that all membership-based organizations, from political parties to football clubs, have suffered major decline in the past 50 years. Voluntary pastimes, by contrast, are king.
"We live in a different sort of society," Ms. Davie says. "Anything that depends on a sense of duty or obligation to bring people to churches is in trouble."
The second argument holds that religion lost its hold on the public as its influence waned in the modern, secular era, but individual churches remained compelling cultural attractions because of their rich historical resonance.
"The attempt to impose Christianity on a culture was fundamentally flawed and took many centuries to unravel," says Dr. Stuart Murray-Williams, a theologian and author of a book, "Post-Christendom," which charts the gradual decline of institutionalized Christianity. "Christianity thrives best in a culture where faith is free."
Mr. Bartley says that the religious heritage industry has become "massive" and claims that there will always be interest in the history of churches.
"But the danger is that it becomes nothing more than that - a historical curiosity rather than something that has contemporary relevance," he adds.
Another argument is that the horrors of the 20th century, such as the Holocaust, made faith a tougher sell. (Worshiping numbers started to taper here after World War I). Yet tragedies today leave people hungering for a sense of peace. Tellingly, during two episodes of overpowering public grief here - the death of Diana, Princess of Wales, in 1997, and the murder of two schoolgirls in 2002 - entire communities sought solace in church.
"Part of it is a search for roots in a time of uncertainty," says Dr. Murray-Williams. "It may be that people turn to church for something they wouldn't call religion, but values, ethos, comfort, identity."
"There seems to be a residual Christendom, which won't go away, whatever it means for regular worship," he adds. "There is something there that still resonates from the many centuries it dominated society."