PARIS (Reuters) - London’s Vatican ambassador feared anti-Catholic violence in Britain after Pope Benedict offered to accept traditionalist Anglicans into the Roman Catholic Church, according to a U.S. diplomatic cable obtained by WikiLeaks.

Catholic-Anglican relations faced their worst crisis in 150 years because of the offer, which undercut the authority of Archbishop of Canterbury Rowan Williams, the cable quoted Ambassador Francis Campbell as saying after the offer last year.

Five Anglican bishops in Britain announced last month that they would join the Catholic Church early next year, in response to the offer made in October 2009 to Anglican clergy opposed to the ordination of women bishops in the Church of England.

The cable, dated November 30, 2009 and published by the Guardian newspaper in London on Saturday, reflected concerns that have since eased. Tensions that it predicted for the pope’s visit to Britain in September this year did not materialize.

The confidential cable, signed by U.S. ambassador to the Vatican Miguel Diaz, said Campbell noted that England’s Catholics were a minority and mostly of Irish origin.

“There is still latent anti-Catholicism in some parts of England and it may not take much to set it off,” it said, paraphrasing his words. “The outcome could be discrimination or in isolated cases even violence against this minority.”

Speaking after the two churchmen met at the Vatican last month, Campbell said the pope had “put Williams in an impossible situation” and the archbishop’s cautious reaction -- meant to avoid harming relations with Rome -- angered some Anglicans.

TRICKLE RATHER THAN WAVE

Diaz ended the cable asking “whether the damage to inter-Christian relations was worth it -- especially since the number of disaffected Anglicans that will convert is likely to be a trickle rather than a wave.”

Another cable dated November 9, 2009 said Campbell told Diaz that the Catholic Church would face “unforeseen obstacles” if many traditionalist Anglicans took up Benedict’s offer.

“A large transition of Anglican converts could overwhelm the financial resources of many dioceses,” it cited him as saying.

The Anglicans most likely to make the switch were the most conservative, he said.

“In uniting traditionalist Anglicans with the Catholic Church, the pope is bringing together two groups strongly committed to defending Europe’s Christian heritage -- a theme he strongly champions,” it added.

The cable cited an unnamed source as saying Williams was probably informed about the offer only a day before it was announced. When he expressed concern about it, he was told the Vatican had made its decision and was going ahead.

According to the November 30 cable, Campbell felt the Vatican had acted without considering what its move would mean for the Church of England, mother church for the world’s 80 million Anglicans, or their spiritual leader Williams.

“The Vatican decision seems to have been aimed primarily at Anglicans in the U.S. and Australia, with little thought given to how it would affect the center of Anglicanism, England, or the Archbishop of Canterbury,” it said in relating his view.

The Vatican announced last month that its first so-called ordinariate for Anglican converts would be established in Britain. Bishops and priests would join the Church in the first half of the year, followed by lay people wanting to switch. (Editing by Tim Pearce)