Rome, February 25 - Cardinal Keith O'Brien, the United Kingdom's most senior Catholic cleric, resigned after accusations of "inappropriate behavior" toward other priests in the 1980s, the BBC reported on Monday. O'Brien is stepping down from his post as Archbishop of St Andrews and Edinburgh. Three priests and a former priest from the Scottish diocese complained earlier this month to the pope's UK representative Nuncio Antonio Mennini for what they claimed was the cardinal's inappropriate behavior toward them in the 1980s, the Observer newspaper reported. Outgoing pope Benedict XVI is expected to accept the resignation, according to the BBC. The resignation throws the Church of Scotland into crisis and strikes a heavy blow to the Church as a whole, as the Vatican battles for its reputation amidst reports of internal corruption, mismanagement and allegations of covering up for pedophile priests in other parts of the world. O'Brien, who was to be Britain's only representative in the upcoming conclave, is not longer expected to take part in the election of Benedict's successor. O'Brien had been planning to retire after the selection of the new pope.