Florida's not-so-coy pastor is just the latest in a plague of fallen preachers

Revelations of extra-marital affairs and a porn habit leave the 20,000 worshippers of one mega-church leaderless

The disgraced pastor Bob Coy, of Calvary Chapel

Ushers walk the aisles with boxes of tissues just in case, but the message to the nearly 4,000 worshippers who have crammed into Fort Lauderdale's Calvary Chapel is to keep upbeat, at all costs. "I just want to tell you," an assistant pastor declares as the service reaches a climax, "this is not the end."

Here in the main sanctuary, surely large enough to host a minor boat show, the congregation is anxious to reciprocate, following the hymns on the giant projection screens above the stage, their arms lifted to the rafters. "This is my prayer in the desert, This is my prayer in the fire, This is my prayer in the battle," they sing. "Everyone needs compassion. Everyone needs forgiveness."

It was a gruelling week at Calvary Chapel, the largest mega-church in Florida and the fastest growing in the land, with full membership at 20,000 and counting. But what happens now is the question. An assistant pastor was on stage on Wednesday night because Bob Coy, the founder and lead pastor, the man everyone wants to see for his saucy charisma and his "I'm-just-like-you" folksiness, has been suspended and exiled for, well, sauciness.

This is familiar territory for the industry that is the US's mega-churches – officially any place of worship with over 2,000 members. There are an estimated 1,200 of them, a few, like this one, with big broadcast interests. Tele-evangelist Jimmy Swaggart was defrocked by his Assemblies of God church in a sex scandal in 1988. More recent was the 2006 downfall of Ted Haggard in Colorado, after a relationship with a male escort.

Fall from grace: Ted Haggard

Those are the famous cases. But Florida alone has seen three other mega-church leaders taken down by scandal in past 12 months, one of whom, Isaac Hunter, later killed himself. And they are just in and around Orlando. By some accounts, America is in the midst of a plague of preacher-turned-sinner debacles.

"I have dealt with near a dozen churches in the past couple years who lost a pastor due to a moral issue," Ron Edmondson, a Kentucky pastor and religious affairs consultant, wrote reflecting on the Coy case. "One of the leaders in our denomination used the word 'epidemic' to describe the number of pastors leaving the ministry because of moral failures."

The Calvary Chapel's statement last weekend revealing Pastor Bob's fall was bland. Married with two teenage children, he had succumbed, it said, to "moral failings". That, say the reports, had involved extra-marital affairs and a compulsive pornography habit. Coy himself has not been heard from and the church is in media shutdown. Indeed, this reporter was escorted off its premises.

There is a special poignancy to Coy's fall from grace. He has previous, which was actually central to his appeal. He founded the church in a shop back in 1985 after coming here from Las Vegas, where he admitted using cocaine and managing a casino with strippers. It was a brother, Jim, who took him by the scruff and told him there was another, Godly, path.

"The next morning I wake up and everything's changed in my life and in my heart," he recounted in one interview. "I drove back to the casino, and I walked in. I looked around, and I saw naked girls. It was like, 'Oh, I work here? Oh, boy.' God began to convice me in such a gentle and lovely way that I don't belong here. It's time to make a change in my life."

That story of redemption attracted people like John Fantom, 53, a telemarketer who has attended the church for seven years. "I have been about a bit in my life," he said, glancing at his feet. "He gave me hope because he has been a sinner and because I am a sinner. We are all hypocrites."

Dwayne Clark, 23, was also at the service, agreed: "Satan loves this stuff. He and his demonic goons will do anything to attack the body of Christ and crush his teachings. But Pastor Bob will rebound from this."

That may not be so easy, suggests Professor David Kling, chair of the University of Miami's religious affairs department, who does not see Coy returning. Nor will it be easy for the Chapel to survive, at least with its nine campuses, 32 pastors (make that 31), $40m (£24m) in annual donations and 600 employees.

"Calvary Chapel was Bob Coy and Bob Coy was Calvary Chapel," said Professor Kling, citing US religion's "entrepreneurial" tradition dating back to the 19th century. "It's one thing for a Steve Jobs to leave Apple, but here you have an organisation which is voluntary. No one is requiring anyone to show up. Once Bob Coy is gone, who knows what will happen."

For now though, Coy's followers have to come to terms with what has happened, says Rob Hoskins, leader of One Hope, a global ministry for children based two miles from Calvary. "It's been shocking for people in the church. It is very devastating and painful for us. This is similar to grieving."

He also doubts a Coy comeback. But to ask now is premature, he says. "First he has to reconcile to his Lord, he has to reconcile to his wife and he has to reconcile to his children."