A prolific thief broke into the vestry of a North London church; grabbed the weekly collection, an iPhone and some silver, and began his getaway. He pushed past a female curate and raced towards the exit, but Father Andrew Cain got to the doorway first. Tall and broad-chested, he bellowed: “Get on your knees!”

The ecclesiastical citizen’s arrest was widely celebrated in Britain at the time. Two years later, Cain is about to make headlines again, but this time his career is hanging in the balance. Defying the church’s orders, he will become the first Church of England clergyman to enter into a same-sex marriage.

The church, which is at the heart of the 80 million-strong worldwide Anglican Communion, has always defined marriage as a contract between a man and a woman, and it refused to recognize Britain’s legalization of gay marriage, which comes into force at the end of the month. Church officials are furious that Cain is ignoring a ruling by the House of Bishops, which bans clergymen from performing same-sex weddings in their churches and orders gay vicars not to marry.

Disregarding the diktat, Cain, 50, and his fiancé, Stephen Foreshew, 40, officially registered their intention to marry at Camden Town Hall in London last week. They want to keep the location of their June wedding secret in case it attracts unwanted attention, but concede it won’t be taking place in a church despite Cain’s 28 years in the clergy. “I’ve always loved the job, but I’m finding it really quite hard to love the Church at the moment,” he said, stroking one of his two handsome Bengal cats. “I feel very angry and quite bitter about the way the church is behaving.”

The priest, who oversees two parishes in North-West London, disclosed to The Daily Beast that he had been hauled in front of his bishop last week. Cain said he was summoned to the home of The Rt Revd Peter Wheatley, Bishop of Edmonton, along with a church human resources officer, and reprimanded for his open defiance of the ecclesiastical guidelines.

“He was offended about the fact that I was being public in my opposition to the bishops, and I said, ‘Well, actually I think you are wrong and I’m sorry but this is conscientious dissent,’” Cain said. “I’ve known him for 15 years—it was an extraordinarily awkward and difficult thing.”

Cain said the bishop tried to convince him to abandon his wedding plans and ordered him to stop criticizing the church’s position. The Church of England has no formal guidelines for bishops on handling members of the clergy who disregard rulings on gay marriage, but a church official said Cain could be sanctioned or even dismissed for “conduct unbecoming” the clergy. Wheatley declined to comment on the meeting.

The Church of England, which broke from the Vatican in 1534 so that Henry VIII could take a second wife, has often been celebrated for its accepting and open attitude. In fact, Cain estimated that a third of the clergy in London are gay. A clergyman, who did not wish to be named, claimed that at least 13 of the church’s 42 bishops were also gay, although they have not publicly acknowledged it. “Gay people have very often a heightened sensitivity to things of beauty and spirituality,” Cain suggested. “There are an awful lot of gay people in the church.”

For generations, gay priests were accepted into the church as long as they were willing to keep quiet about it. This “woolly” approach to religious doctrine has been sorely tested in recent years with the church divided over female bishops and gay marriage. Confronted by the British government’s introduction of gay marriage, the church was suddenly faced with a dilemma: About a third of British weddings are currently held in churches, leaving the bishops to decide whether they would open their doors to a new set of marriages.

The most senior clergyman in the Anglican Communion, Justin Welby, the Archbishop of Canterbury, acknowledged that the attempt to uphold traditional teachings was becoming problematic. “There is a great fear that our decisions will lead us to the rejection of LGBT people, to irrelevance in a changing society, to behavior that many see akin to racism,” he said.

Despite his warnings, the House of Bishops issued an unexpectedly stringent statement on Valentine’s Day. There would be no same-sex weddings in churches, no prayer ceremonies—unless they included a reprimand for the couple—and absolutely no gay clergy were allowed to marry.

Conservative groups in the church welcomed the ruling. The Rev. Andrew Symes, executive secretary of Anglican Mainstream, said: “The Bible is very clear that same-sex sexual activity is wrong.”

He was among those beseeching Cain to accept the word of his superiors. “In any organization if people go against what their leaders say it’s going to cause difficulties. There is a conversation going on inside the church about this and Mr. Cain presumably feels that he wants to pre-empt that conversation. He thinks he has the right to overturn centuries of Christian teaching just on his own authority,” he told The Daily Beast. “The vast majority of Christians around the world have always believed that marriage is between a man and a woman. we’ve got a Western culture that has decided to change this in the last few years; it’s a small number of people who have taken this view so Mr. Cain is very much in the minority.”

At the center of this maelstrom, it’s business as usual for Cain. This week a massive refurbishment project began at the stunning red-brick St James’ church in West Hampstead, where services were first held in 1880. He has raised more than half a million dollars to transform the church into a café, crèche and the first church in the country to house a major branch of the Post Office.

The chairs, statues and religious icons, some of which date back to the 16th century, were being hurriedly packed away; a pair of Jesuses lay on their backs on the dais.

At the final site meeting before construction began, Cain was in a no-nonsense mood. Dressed in a red blazer, he refused to accept the builders’ apologies for a one-week delay. “Seriously, let’s not start slipping it at the first meeting,” he said. After a spell of futile resistance from the construction team and project manager, they were back on schedule and Cain sat back in his chair satisfied.

“I’ve been told to button my lip,” he said, smiling.

His scheme to re-integrate the church back into the center of this urban community has won Cain a legion of admirers. “Until Stephen and I got engaged I was seen as a sort of model vicar for coming up with this idea and pushing it through,” he said. “But I’ve just become a problem now.”

Hopping into his racing green Mini—“Just don’t call me a trendy vicar”—he made his way to the next appointment, a school board meeting. “Allowing women priests was the start of it,” he said on the way. “The same approach to scripture leads to accepting that gay people are gay people. The wishy-washy moderates in the middle accepted women because, ‘well, I’m married to a woman’ or ‘it just seems like the right thing to do’ but they hadn’t thought about the theological implications.”

When the House of Bishops made its ruling, Cain was appalled. “It makes us look like Neanderthals quite frankly. We look like racists,” he said, as he weaved in and out of the busy London traffic.

Each church within the Anglican Communion, which continues to spread and grow from its roots in the Church of England, has taken its own view on gay marriage. Gene Robinson became the first openly gay clergyman to be consecrated as a bishop in the U.S. Episcopal Church in 2003, while some of the African churches have taken increasingly conservative steps.

“The Ugandan church has just announced that it’s going to start performing exorcisms on people to cure them from being gay,” he said. “One would hope, in all Christian honesty, that the Church of England would speak out. There’s a sort of strange reverse-colonialism where the bishops in the West don’t feel free to criticize the African bishops, and if we do the Africans accuse us of colonialism, well actually no, you’re just plain wrong and you’re doing bad things. They’re all a bit conservative and nasty.”

Fred Phelps, who died last week, was another churchman with unfavorable views on homosexuality. “May he rest in peace,” Cain said. “I think he was a very sad and rather pathetic person really, I take no pleasure in any man’s death I just hope he now sees the error of the way he’d been behaving. If we believe in heaven and forgiveness when he gets there he’ll be in for a terrible shock.”

Cain did not intend to become a cause célèbre. He proposed to Forshew on February 14th, the same day that the bishops were deciding to curtail the clergy’s access to Britain’s new gay marriage laws. “The bishops made it an issue of it, not me,” he said.

Forshew, an IT director and atheist, said he was terrified that his partner’s openness could bring a premature end to his life’s work. “I find his bravery extraordinary,” he said. “If punitive action was taken by the church it would be very painful and extremely traumatic for him.”

Cain’s place in history was secured over a steak dinner cooked at home on Valentine’s Day: “I made Stephen’s favorite meal and at the end of it I said, ‘Will you marry me?’ And he said, ‘Get down on one knee,’ and I got down on one knee and said will you marry me? And he said yes.”