The former Archbishop of Westminister has warned that the new Pope "will not be a saint, straight away" as the Vatican once again prepares for a conclave where abuse scandals will dominate cardinals' discussions.
Cardinal Cormac Murphy-O'Connor said he was "saddened" by the resignation of Britain's most senior Roman Catholic, Cardinal Keith O'Brien, who was to have been the UK's only representative at the conclave. Aged 80, Cardinal O'Connor is now too old.
Cardinal O'Brien has been accused of inappropriate behaviour towards priests in the 1980s, in an investigation by the Observer. He denies the allegations but has stepped down from his position.
In a news conference, Cardinal Murphy-O'Connor said the recent abuse scandals and reform of governance will be top of the cardinals' agenda in choosing a new Pope, as well as a man who could create dialogue with the Muslim world.
Asked by HuffPost UK whether it was important a new Pope be free from any taint of scandal or cover-up that has so dogged the Church in recent times, Cardinal Murphy-O'Connor said: "You are not going to get a saint straight away. We are all sinners. But the man they elect will be of irreproachable character and that's as far as you can expect."
The new Pope must be "a truly spiritual man" and "a bridge builder."
He said he regarded Cardinal O'Brien as a "friend" and was deeply saddened by his departure, which he was told about the night before. "I am very sad indeed, but it will be investigated. He will not attend the conclave, but I think the Cardinals will be discussing these issues, and others that concern the reform of the Church.
He insisted that Cardinal O'Brien had not been forced out by the Vatican. "It's a matter for his own conscience. He decided to do it, he wasn't asked. I think he thought it would be a distraction.
"It was his decision, he was not forced or asked. He thought, given the publicity, despite the fact that these allegations are being contested, that it was the right thing to do."
"The scandals have to be addressed, and there is no doubt in my mind they have to be addressed at the highest level and there has to be reform. I think that will be one of the main things that the cardinals will be discussing.
"When a new Pope is elected, he will know that very well, and have been part of the discussions, and go to his post with a very clear mandate.
"If the scandals are not addressed, and this is something that saddens me greatly, that not just the image of the church but the effect of the church, preaching the gospel of Jesus Christ, is lessened.
"Especially the Pope’s own house has to be put in order."
Cardinal Murphy-O'Connor said he could not advise other Cardinals, some of whom have also been linked to alleged abuse cover-ups, whether they should attend conclave, but indicated the obligation to attend went beyond personal desire. "It is up to them, up to their own conscience. I think I ought to say that there is an obligation on Cardinals to go to conclave."
Other issues which could be discussed at conclave could be celibacy and dialogue with the Islamic world, Cardinal Murphy-O'Connor said. "I think that might be a matter that may well come up, the ordination of married man. I don't think it'll be first on the agenda but it may come up.
"There must be dialogue with other faiths, Hindus, Jews, Buddhist, but especially Islam. That dialogue with Islam will be especially important for the Pope if we are going to have peace in our world.
"I am often asked if we are going to have a black Pope. We could have, we could have a South American, or Asian pope. And we could even have a Pope who is not a Cardinal."
Cardinal Murphy-O'Connor would not comment on remarks by Cardinal Peter Turkson, of Ghana, that an abuse scandal would not happen in Africa because of anti-homosexuality laws. He said he was unaware of the particular interview, but praised the Cardinal, widely tipped as a potential black Pope. "I do like Cardinal Turkson. I met him recently. And said to him, 'you can't open a newspaper without seeing your face.' He's a very nice man."
The Cardinal also shared light-hearted reminiscence of the last conclave, when he helped to choose Pope Benedict XVI. He described the moment Cardinal Joseph Ratzinger was told he had been elected.
"He said at first 'No, I can't', then he said, 'I accept, as the will of God'. And then the conclave said to him, Your Eminence, what name will you take? And he said straight away I will pick 'Benedict'. He might have thought about it the night before. Perhaps all the cardinals have a name up their sleeve.
"There's a tailor who makes three white cassocks, one large, one medium and one small.
"And he comes back, dressed in his white cassock, and we followed him out to the balcony, where he was announced to the huge crowd. It was extremely moving and solemn."
Cardinal Murphy-O'Connor did express regret that no UK representative would attend the conclave, because the current Archbishop of Westminster, Vincent Nichols, has not been made a Cardinal. "I am very sorry that my colleague Archbishop Vincent has not been made a Cardinal but the main reason for that is me.
"If I were dead, he would already be a Cardinal. I am sure he will become a Cardinal before very long."
The Vatican announced on Tuesday that retired Pope Benedict XVI will be called "emeritus pope," and continue to wear white.
Pope Benedict, 85, announced earlier this month that he is to resign, the first pontiff in nearly 600 years to do so. He will formally quit on Thursday as leader of the global Catholic Church.
The German-born pope, who was elected in 2005 after the death of Pope John Paul II, said he had decided to resign because of his age and infirmity.