LONDON — Britain's ambassador to the Vatican feared the pope's invitation for disgruntled Anglicans to switch to Catholicism might spark anti-Catholic violence at home, a leaked US diplomatic cable revealed Saturday.

Ambassador Francis Campbell told US diplomats that "Anglican-Vatican relations were facing their worst crisis in 150 years as a result of the pope's decision", according to the cable dated November 30, 2009.

The cable sent to Washington added: "The crisis is also worrisome for England's small, mostly Irish-origin, Catholic minority, Campbell said.

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

Campbell was speaking to the United States' deputy chief of mission to the Holy See, Julieta Noyes, following a recent visit to Rome by Archbishop of Canterbury Rowan Williams, the head of the worldwide Anglican church.

The previous month, Pope Benedict XVI had made it easier for Anglicans disaffected by moves to ordinate women and homosexual clergy to join the Roman Catholic Church.

Five Church of England bishops, two of them retired, have since converted.

Campbell was quoted in the US cable as saying the move had "shifted the goal of the Catholic-Anglican ecumenical dialogue from true unity to mere cooperation".

It also put Williams in "an impossible situation" in trying to maintain unity within the Anglican church, he was quoted as saying.

In September, the pope and Williams used the pontiff's state visit to Britain to make a symbolic show of unity by holding joint prayers.