Cardinal Keith O’Brien, who stepped down as Britain’s highest-ranking Catholic cleric last week amid allegations of inappropriate behavior with priests, backed away from earlier denials and admitted Sunday to committing acts of sexual misconduct.

The admission was a blow to the church’s hierarchy even as cardinals prepare to meet in Rome on Monday to select a date for the conclave to pick a new pope. In Britain, the admission was considered a confirmation of what observers here have called a prime example of church hypocrisy, given that O’Brien, 74, emerged as a leading voice against gay rights.

washington post