The inquiry by the Vatican into the sexual conduct of Cardinal Keith O’Brien is not likely to begin until after a new Pope is chosen – with the former Archbishop of Westminster saying the Catholic Church is made up of “saints and sinners”.

Cardinal Keith O’Brien quit last Monday as Britain’s most senior Catholic following allegations of inappropriate behaviour by several priests in the 1980s.

On Sunday, in a display of contrition, Cardinal O’Brien said: “my sexual conduct has fallen below the standards expected of me as a priest, archbishop and cardinal.”

“By his own admission, the cardinal stands exposed as a hypocrite. He preached publicly against homosexuality while privately seeking its pleasures,” human rights campaigner Peter Tatchell said to PinkNews.co.uk on Monday.

Cardinal O’Brien’s resignation means Britain will have no representation at the impending conclave, when the Catholic Church’s top cardinals gather to elect a new Pope.

Last Friday, just hours after Pope Benedict XVI officially stood down as Pope, the Scotsman newspaper reported that the Vatican were first altered to the most recent allegation involving Cardinal O’Brien in October 2012 – around five months before his resignation.

The Vatican has already been accused of failing to come to terms with the issue of homosexuality in the Catholic Church.

US LGBT Catholic group Rainbow Sash Movement said in the wake of Pope Benedict XVI’s resignation: “It is now time for the Vatican to sincerely begin dealing with the present realities that face the world wide church. The time of hiding behind the theater of liturgy, incense, bells and music rather than the justice that should flow from that Liturgy needs to come to an end.”

Cardinal Cormac Murphy-O’Connor, a former Archbishop of Westminster, told the BBC that the Catholic Church had not lost its moral authority, but that it was “composed of saints and sinners”.

“Sometimes it is just the weakness of individuals and the wrong that they do,” the cardinal said. “The vast majority of priests and bishops are good and faithful men who are faithful to what they do, to what they preach and their way of life.

“To say that this has sort of infected everywhere is just not true,” he said.

Last December, Cardinal Murphy-O’Connor criticised David Cameron for introducing same-sex marriage in England and Wales and said it was an “abuse of language”.