WHEN Pope John Paul II visited Ireland in 1979, Father Brian D'Arcy had been working his collar off since 4am that morning. By the mid-afternoon he still hadn't taken a break and was desperate to find somewhere to relieve himself.

"I knew there was a toilet underneath the altar, " he says. "I raced down the steps and asked the guard, 'Is that the toilet?' He said it was, so I burst through the door."

It turned out to be a small room with Paddy Hillery and wife, Jack Lynch and wife, Cardinal Tomas O'Fiaich, Archbishop Desmond Ryan? and a hungry Pope John Paul II at the top of the table. "They were disgusted at me bursting in, as they thought I'd gatecrashed the party.

For a man who followed the showbands religiously in the 1960s and snuck out of the Mount Argus to hear the Beatles playing at the Adelphi, Karol Wojtyla was the ultimate celebrity. In telling this story, the spotlight moves from the pontiff in his white robes to shine instead on the skinny little upstart from Bellanaleck in Co Fermanagh, standing in the doorway. "It was a small wee dungeon of a room, " Father Brian, now 60 and still a brunette, says. "The pope was tearing into his beef and I froze. He was heading off to Drogheda for the second part of the day and was not pleased to be leaving his dinner. In fact, he was quite angry and, as he passed, he gave me a look that would turn milk."

But this brush with international celebrity was not over yet. "Tom O'Fiaich, gentleman that he was, said, 'Come on up here and take his chair because it will be the nearest you'll ever get to being pope.' And I ate the man's dinner!" Father Brian still laughs at this, though it is nearly 30 years later. It is that same non-stop chuckle you might remember from his many appearances on the Late Late Show since the 1980s.

Paddy Hillery and Jack Lynch apparently finally got the joke.

"It was a lovely cut of beef, I have to say, " Father Brian adds, putting the finishing touches to this well-honed tale. The pope must have had a lot of dinner left. "Well, " he replies, "I think he got a second helping."

We are sitting in the noisy café of the Great Southern Hotel in Dublin Airport - another sign that Father Brian, pastor to the entertainment industry, broadcaster on BBC Radio Ulster and columnist with the Sunday World for 30 years - is still constantly on the move. He has played major roles in Irish popular culture, rescuing the tapes that became Give Up Your Auld Sins, and along with the late Father Michael Cleary - champion of single mothers and creator of at least one - becoming the prototype for Dermot Morgan's Father Brian Trendy, who later morphed into Father Ted. "I did find it irksome, " Father Brian says, "though Father Ted was more like a cartoon; it was the same every week."

Because of his TV appearances, I think of him more as the Laughing Priest, rather than Father Trendy. I call him "Father Brian" in print to be polite, but I address him as simply "Brian". On the cover of his recently published memoir, on the telly. (He is also out of uniform today. ) Why mess with the brand? "It would have been more commercial to have Father Brian D'Arcy with the collar on me. But it's not about Father Brian D'Arcy, it's about the man. Priesthood doesn't define the man."

Father Brian's autobiography is a rollicking good read. It covers his horrific early years in the Passionist seminary where he was abused by an older priest and students were deprived of hot food, sleep and warmth - one of the oldest brainwashing techniques in the book - and encouraged to flagellate themselves with knitted cord. It is also a social history of showbands like the ill-fated Miami Show Band, attacked by loyalist terrorists (and at least one suspected British soldier, according to a surviving band member Stephen Travers). Amidst his personal struggles and triumphs, he also muses on the reversal of fortune of the Irish Catholic church over the last 50 years.

One of the most gripping stories involves the 1987 kidnapping of dentist John O'Grady by Dessie O'Hare. Father Brian was charged with delivering the £1.5m ransom. He believed he could be driving to his death: O'Hare had already cut off the tops of two of O'Grady's fingers and threatened to saw off his legs. On this most secret of missions, he was told he would have to drive to different locations until nightfall. When he stopped at a petrol station, the attendant asked, "Are you on the way to meet O'Hare with the ransom money?" (Only in Ireland, right? ) Someone had leaked the story to the Irish Independent. O'Hare was found in a house in Cabra before the money was delivered.

The book is also littered with those pictures of Father Brian with the other man in black Johnny Cash, Bill Clinton, the Duke of Edinburgh, Kenny Rogers, Reba McEntire, Terry Wogan, Tina Turner, Gilbert O'Sullivan, Barry McGuigan;

Father Brian blessing the big top at Fossett's Circus; and - my personal favourite - in a Daniel O'Donnell-Cliff Richards perma-tanned sandwich. (During one photo-op with the buxom Dolly Parton, she reminded him to look at the camera. ) And the padre, always smiling. In fact, when I arrived earlier for our sandwich and pot of tea, I almost passed him in the foyer because his face was in repose. Without that signature smile he was barely recognisable.

As one reviewer - Kate Holmquist in the Irish Times - understandably suggested, Father Brian must have had a camera on his person at all times. So, was he chasing celebrities with a disposable snapper? "I never had a camera and I didn't pick the photographs for the book. I had hardly any of my own. People who know me in Enniskillen have laughed at that suggestion." Then he laughs, again. "Somebody gave me a digital camera and I gave it away the next day. Kate has an opinion, she's entitled to it; if that comes through in the book, she's more entitled to it. But I don't think it's correct.

It doesn't carry through. I'm at it 40 years. You grow tired of celebrity very quickly."

He stops chewing his sandwich. "I've seen the celebrities come and go and I've seen the guys who wanted to be part of the all-priests show." (That's a group of all-singing, all-dancing travelling priests. ) "I was the chaplain who let the entertainers be entertainers. I'm quite content in my own mind that it wasn't celebrity that was keeping me going because celebrity in clericalism is absolutely scorned upon. The difficulty in my life is that most priests think I am a celebrity."

He comes over all humble. "I'm around long enough to be a habit. I'm not a celebrity. You drift in and out of people. It could be a year and I wouldn't be on television at all and then I could be on four times in one month."

Terry Wogan writes in the forward of the book that Father Brian didn't do it for fame, fortune or applause. Father Brian himself insists he didn't believe he had a life that warranted a biography, but was persuaded by publishers and friends. (He writes, "To this day, I'm often crippled by my own unworthiness.") And tells me, "Almost all the major Late Lates I've been on in recent years was because they couldn't find anybody else." Is he backing into the spotlight? Surely, the bigger the celebrity, the more producers must cajole and, at least, act like they know it would be an inconvenience for the prospective guest to come into the studio. As Bertie would say, who's he coddin'?

"It is true! It is true! If you ring Pat Kenny he'll tell you very clearly they would look for a priest to talk about abuse and they couldn't find one. On one occasion, they rang me at five o'clock in Enniskillen and they said, 'Brian, can you possibly get down and do it? We'll send a car for you, we'll do anything, but could you please, because we have a discussion tonight on abuse and we can't get a priest to come on.'" Why not?

"How could they defend the church and they couldn't go on and not defend the church. What I had to do was be honest with myself and say, 'It's wrong and I do apologise to you and as a person of the church.' A celebrity would pick the gigs that were good."

While reaching a one million-strong readership every week with articles on the disenfranchised, and speaking against celibacy and Rome's treatment of sexual abuse victims, I suggest he may still be a little naïve when it comes to the media. After an interview with Joe Jackson in Hot Press in which he revealed that he had been sexually abused, the Star ran the headline: "Father Brian D'Arcy Admits He Was Sexually Abused". Father Brian cried when he saw it.

He was upset by the use of the word "admit", which implied he was confessing some great wrong, when it was clearly he who was wronged. But surely he knew the story would be picked up and sensationalised?

He leans across the table. "I'm long enough to know what was planted and what wasn't planted, " he says. "I know the journalist in question and I know who it was. I'm quite certain that Joe Jackson didn't do it. The story was, 'Yes, I was, but I'm not talking any more about it.' If I had gone on about it for 20 minutes, then you would have seen the story and picked it up. It was three lines buried in the interview." On the subject of that abuse in the seminary, he adds later, "Eighteen in 1963 is not 18 today. A 10-year old now would run a hundred mile from it. It's not at all your fault, but you keep blaming yourself and that's why it destroys a life. Your confidence and self-image does go."

The same Passionist who abused him summoned Father Brian on his deathbed and asked him to say some words at his funeral. He, unbelievably, agreed. As he says, manipulated to the end. But he has been less swayed by the institution itself.

He particularly criticises Pope John Paul II for praising and defending the notorious Mexican priest Father Marcial Maciel Degollado, the founder of the Legionaries of Christ, who was restricted from saying public mass. Rumours dogged the founder of the Legionaries since 1956 - when he was accused of theft and drug abuse - but as late as 2004 Father Brian says the then-pope congratulated him. "He protected and honoured him, " he adds.

Trendy or not, he's right about a lot of things, including the handling of Bishop Eamonn Casey of Galway, who crept out of the country - before the Annie Murphy revelations broke - like a pantomime villain in the dead of night. At the time, Father Brian told a bishop, "Don't let him run because it will be a disaster." He probably rightly believes that the fallout was the beginning of the erosion of our faith in the Catholic church, but not even he could believe that his friend of 20 years, Father Michael Cleary, had had an affair with his housekeeper, the late Phyllis Hamilton, which she disclosed after the priest's death. How could he not know something like this about one of his best friends?

"Michael was known for helping a whole lot of unmarried mothers when nobody else would do it and that was the story, " he says. "I know that is hard to believe, but Phyllis herself was very adamant that nothing was going on. I called into her the night he died and she produced a letter. I was horrified. I just thought she must have been really upset. In the past, she'd have taken legal advice against anyone who said that they were." When he said he didn't believe it, he says Phyllis unleashed a series of abusive phone calls and faxes. "I have no idea why the church still insists on mandatory celibacy and I can't understand why people don't recognise that during Michael's life he did a lot of good."

On page 184 of his autobiography, Father Brian makes the most startling statement of all. The happy-clappy priest writes that something died inside himself in 1993, adding, "I simply don't trust anyone implicitly ever since, not even close friends." Isn't that lonely? And harsh? "I think half of that might be because of the abuse. But I really did trust Michael.

How could you drive around the country with somebody who would not tell you? I've seen so much of the wrong side of human nature it's very hard to say that, given certain circumstances, somebody would let you down. I thought a long time about writing that line. I took it out and put it in several times. But it is how I feel."

The priesthood, like the military, appears to attract the poorer, vulnerable, less educated in society, I say. He sees some similarity. "Very rarely do you get a highly educated person here in Ireland becoming a soldier; they go into the air corps. But you always have foot soldiers and you always have leaders." Which is he? "I'm definitely a foot soldier. From my background and mentality, I'm not an institutional leader, though I may have become a leader in other ways." He clashes frequently with Rome. "I never, ever, ever accepted the Vatican document which says being gay is intrinsically evil. If God made a human being that way, then whether we agree with it or not is irrelevant."

He once told Joe Duffy on RTة radio that he was once in love with a woman. "I was genuinely surprised that people did not understand how a guy could reach 50 and not fall in love." Was it unrequited? "It was a very healthy situation and we respected each other in it and made the journey together. I've had many, many friends who are women. People say, 'Which one was it?'" But he never will tell. He never broke his vows but, I ask, did he experience a passionate embrace or a stolen kiss? "No, if you got into that you'd be in big trouble. It's not fair to the other person or yourself." He falls silent.

"Companionship, understanding and feeling at home with each other. They are lovely gifts."

In a mass pre-cleansing before Christmas, Father Brian and his Passionist brethren must conduct five-hour marathon confessional shifts every day. Tonight, Christmas Eve, he will say midnight mass in Enniskillen and, on Christmas Day, get up at 3am to drive to Belfast for his BBC show, then drive two hours back for 12 o'clock mass. "I stay on duty for the rest of the week and let the rest of them go home." So, does this pastor to the stars enjoy his own company - out of the limelight?

"I drive 50,000 miles a year on my own, so I have to. I love walking, along a cliff or on a beach, being in nature and clearing my mind. That is as near to heaven as you can be. That is when I feel closest to God."