Tony Flannery is upset at being labelled a "radical fringe priest" in a recent newspaper interview. "My book is written by someone involved in the priesthood up to their neck," he protests. "This week, I am preaching at a nine-day novena in Tuam. You can't get more traditional and churchy than a novena."

Flannery (52) is talking about his second book, From the Inside: A Priest's View of the Catholic Church, which was published in January. The book became a bestseller, and is now going into a fifth edition, having sold 10,000 copies. From the Inside is a frank and outspoken account of holding religious orders in an era when the church has changed irrevocably. Flannery writes: "Almost 25 years later, I find myself firmly of the view that compulsory celibacy does not work." He is equally assertive about his view of the Pope: "I have never been, and as time goes on I am even less, an admirer of him. He has been far too autocratic and dictatorial in his style of leadership.

"I hoped that this book would be a book that the ordinary Irish Catholic would want to read," Flannery explains. What does he think constitutes an "ordinary Irish Catholic" in the late 1990s? He corrects himself. "Well, I'm not sure there is such a thing as an ordinary Irish Catholic these days. The readers I had in mind for this book were people who were interested in church life and faith and who would have a lot of questions about it."

Flannery was the youngest of four, all of whom preceded him into religious life. At 12, he entered a junior seminary. "The world of choice didn't exist then," he stresses, citing mobility and increased employment opportunities as a major reason why religious vocations have dropped so sharply in the intervening years.

"I don't regret becoming a priest. I have had a good life," he says, "but clearly I did not have a full choice in what I did. Then again, how many of us have full choices in our lives?" Two of Flannery's siblings later left religious life. Flannery himself has been in the religious life for 35 years, and is based in the Redemptorist House in Athenry, Co Galway.

He believes he is giving voice to many Catholics in his book. "The views I express in the book are widely held but aren't being expressed a lot by either lay people or within the clergy itself." His first book, The Death of Religious Life? which was published three years ago, was aimed mainly at a religious readership, and "didn't sell anything like as widely". He thinks the lay community are buying very many copies of From the Inside.

`The revelations about Bishop Casey neither surprised nor shocked me. I suppose I had come to know too much about human nature in general and about priests in particular, to be easily shocked," he writes, with unusual and refreshing honesty.

"What I say in my book has resonance with a lot of people," he explains. "The general reaction I'm getting - certainly from the lay community - is that `I could have written those things myself because I felt the same way about them'. As for the religious community, I would consider that I am representing many of their unsaid views also."

What does Flannery see as the biggest change in the development of the church since he joined? "That people now attend Mass of their free will. They're not being coerced into going, in the way they were before, with social and family pressures." The fact that the numbers attending Mass have decreased greatly in recent years does not trouble him; he takes the view that those who are there really want to be there, unlike previous decades.

Flannery is clear that he considers child abuse to be the most damaging of all the darknesses which have come to light within the Catholic church in this country. As a child, he was abused himself, although not by someone in the church. He is ambivalent in his meditations on this in the book.

"Was this (becoming a priest) my subconscious way of escaping from sex, trying to assuage my guilt and shame and placating an angry God? Who knows? . . . At the time it was important and it has had its effects, whatever they may be. But I have moved on."

Does he think the Catholic church is a more open and honest place now for all the revelations which have emerged recently? "I think it is more weakened in terms of its powers, but then, the church should never have had those powers in the beginning."

Flannery says he came to writing late in life. He hopes to write more books. "I think I'm good at it." Meanwhile, From the Inside is still in the bestsellers lists.

From the Inside: A Priest's View of the Catholic Church, by Tony Flannery, is published by Mercier Press at £7.99.