Like the Peter Finch character you may have seen in TV3's screening of Network last night, they are "mad as hell" with Rome. And they "are not gonna take it any more."

Sister Lavinia (52), a nun since she was 17, author of 18 books on spiritual themes, regular contributor to the BBC's Thought for the Day programme, leader of a daily service on Radio 4 and of worship in the BBC World Service, lecturer at the Cambridge Theological Federation and recipient of an honorary doctorate from Birmingham University (for her work on spirituality), has asked to be released from her vows.

This follows 18 months of "relentless pressure" from the Vatican's Congregation for the Doctrine of the Faith to get her to recant and to state publicly that she supports Humanae Vitae, the church document banning artificial contraception, and Ordinatio Sacerdotalis, the church document banning women priests.

She expects to be no longer a nun within a few weeks. Her leaving the Institute of the Blessed Virgin Mary, a sister congregation of the Loreto order, is not a defiant gesture to get up the noses of those who must be obeyed in the Vatican. It is to relieve her beloved order of any further pressure from on high.

That pressure has been concentrated on her superior general in Rome, Sister Annunciata Pak, a Korean and the first non-European head of a major women's order.

The Congregation for the Doctrine of the Faith, which enunciates what is and is not Catholic doctrine and disciplines those who do not conform, has never communicated in any form with Sister Lavinia. Their dealings have been through Sister Annunciata. Nor has she seen any of that correspondence. Sister Annunciata has thought it best to shield her. The correspondence, she said, was "too painful for me to see".

Sister Lavinia's troubles began in 1993, when she published a book about female priests titled Women at the Altar. It was at a time when the issue was being widely discussed, particularly in the UK, where the Anglican Church was then in the throes of debate on the issue.

The book, which approves of women priests, was condemned by the Congregation for the Doctrine of the Faith. When the Benedictine St John's Press in Minnesota reprinted it about 18 months ago the local bishop intervened. She has been told since that copies had been warehoused and/or burned.

"I've no idea of the truth. I can't get a straight answer from them (St John's Press)," she said. And the Vatican began to lean on her superior general to get her to recant.

Two things decided her to go public last week about seeking a dispensation. A colleague died recently after a long battle with cancer, and Sister Lavinia decided life was too short to continue "going around with one hand tied behind my back". And she was in New York at Christmas. She read a report there that three million people attended Mass in the city on Christmas Day.

She estimated that at least 90 per cent of those New Yorkers did not support the church's teaching on contraception. It struck her as unfair and unjust that the church should, through its silence, apparently assent to the right of those lay people to follow the dictates of their own conscience on the issue while she, a nun, was being persecuted for doing just that.

She wondered whether the contributions in New York that day had anything to do with it. "Was the [estimated] $10 million traded for church people's silence on the use of contraceptives?" she asked. The "hypocrisy" struck her "with such brutal force." It was time to act.

SHE reflected on the words of her friend and mentor, Cardinal Basil Hume. He had been "hugely supportive" of her. When her troubles began with the Vatican he told her he had been a bishop for over 20 years "and I honestly don't care what they think". Encouraging her, he said: "Lavinia, this is not about obedience, it's about justice." She decided to seek release from her vows.

She remains a Roman Catholic, as though for her an alternative was possible. She knew only Catholics until she was 12 in her home city, Birmingham. She was baptised by Father Denis Sheil, the last novice accepted to the Birmingham Oratory community by Cardinal Newman himself. As a result she sees herself as the cardinal's "spiritual grandchild".

Her background is "deeply Irish" with two grandparents from this country. One, in Birmingham, was a doctor from a family of 17. She is a relative of the State Pathologist, Dr John Harbison. Others in the family were involved in "the indiarubber business."

Two played cricket for Warwickshire, and one was captain of the England rugby team at a time when that was "remarkable for a boy brought up in a Catholic ghetto." Another grandfather was doctor to the Lord of the Rings author, J.R.R. Tolkein.

Referring to this staunchly Catholic middle-class background in England, she finds it "appalling that these people in the Vatican didn't bother to find out where I came from."

To date all her earnings and royalties have gone to her order. But with release from her vows she should be allowed hold on to her salary from the Cambridge Theological Federation, where she is to teach for at least two more years. Accommodation comes with the job. After that she has no idea. "God only knows," she says.

But for now she feels "happier than I have done in a couple of years, when I had one hand tied behind my back out of loyalty [to the Vatican]." And it was loyalty which inspired her to seek release from her vows and go public with her pain, she said. Loyalty to God.