The first openly gay Anglican bishop, Gene Robinson, has called for the Roman Catholic church's attitude to homosexuals to be confronted.
The Bishop's ordination in America sparked protest
The Bishop of New Hampshire said the Vatican's ban on ordaining gay men was "vile", in a speech in London.
He received a standing ovation after his speech, in which he spoke of how he had faced prejudice in his role.
Some Anglican conservatives had called for the St-Martin-in-the-Fields church venue to be changed to a secular one.
Bishop Robinson said: "We are seeing so many Roman Catholics joining the church.
"Pope Ratzinger may be the best thing that ever happened to the Episcopal Church."
He continued: "I find it so vile that they think they are going to end the child abuse scandal by throwing out homosexuals from seminaries.
"It is an act of violence that needs to be confronted."
His speech at St-Martin-in-the-Fields, in Trafalgar Square, was part of the 10th anniversary of the gay rights group Changing Attitude.
He had been asked not wear his full vestments or take part in the religious service before addressing the audience from a lectern rather than the pulpit.
"I'm here to encourage you to talk about God," he said.
"I am not here to talk about a social agenda. I am not here to grind any axes, I am here to do the thing that Christians do, that is to witness to the good of God."
The London Diocesan Evangelical Fellowship, which includes senior lay and clergy members, had urged the Archbishop of Canterbury to move the Bishop's talk to a secular venue to prevent "damaged relations" between sections of the church.
The Bishop said his home state in the US was "the one place in the world where I am not the gay bishop - I'm just the bishop... it is a wonderful feeling".
He said homosexuals would eventually be fully welcomed in the church but warned that it may take some time.
"This is going to end with our full inclusion," he said. "We won't live to see it, but it's going to happen."
On Thursday the New Hampshire bishop met Archbishop of Canterbury, Dr Rowan Williams, and said he wanted to help heal the rift caused by his consecration, but would not give up his post.
His conscecration two years ago attracted widespread criticism from the more conservative African and Asian sections of the church.
Changing Attitude is an organisation which calls for the Anglican Church to "fully accept, welcome and offer equality of opportunity to lesbian, gay and bisexual people".
He is due to address a congregation in Stockport later on Sunday.