London ? A Vatican cardinal warned the Church of England that any move to consecrate women as bishops would make it impossible for their churches to fully reunify.

Cardinal Walter Kasper, head of the Pontifical Council for Promoting Christian Unity, made the remarks at a private meeting of Church of England bishops, who are exploring the possibility of consecrating women bishops.

Three Anglican provinces, including the U.S. Episcopal Church, already consecrate women bishops. The 77 million-member Anglican Communion, a loose association of churches that trace their roots to the Church of England, has been engaged in ecumenical talks with the Vatican for decades. But if the Church of England ordains women bishops, the goal of restoring full relations “would realistically no longer exist,” Kasper said.

In a statement following the speech, Archbishop of Canterbury Rowan Williams, the communion’s spiritual leader, thanked Kasper for his honesty. “Nothing is served by avoiding these hard questions,” Williams said.

Williams is scheduled to go to Rome in the fall for his second meeting with Pope Benedict XVI.