Blair's Plan to Convert Started in No 10

Tony Blair began formal instructions to convert officially to Roman Catholicism four months before leaving office, it emerged last night, after it was confirmed that the former Prime Minister had achieved his long-held desire to leave the Anglican church and adopt the Catholic faith.

He was formally accepted into the church during a Mass led by Cardinal Cormac Murphy-O'Connor, head of Catholics in England and Wales, at Archbishop's House, Westminster, on Friday night. Before receiving full communion, Blair, now a Middle East peace envoy, would have had to confess all his sins.

His conversion followed a period of doctrinal and spiritual preparation under Monsignor Mark O'Toole, private secretary of Murphy-O'Connor, the Archbishop of Westminster. A source close to the Vatican told The Observer that he had actually begun the course of instruction adult converts must undertake in February, while still at 10 Downing Street.

Last night his former spokesman, Alastair Campbell, who once famously told reporters 'We don't do God', said: 'He has wanted to do this for some time, and now he's done it. It is something that matters to him a great deal.'

Murphy-O'Connor said he was 'very glad' to welcome Blair: 'For a long time he has been a regular worshiper at Mass with his family and in recent months he has been following a program of formation to prepare for his reception into full communion.'

The Archbishop of Canterbury, Dr Rowan Williams, said: 'Tony Blair has my prayers and good wishes as he takes this step in his Christian pilgrimage.'

One of Blair's final official engagements before leaving office was a visit to the Vatican in June, during which he met Pope Benedict XVI. Lady Carla Powell, sister-in-law of Blair's chief-of-staff Jonathan Powell, a Catholic and close friend of the Blairs who accompanied them to the meeting with the Pope, said she thought it was 'marvelous news'. She added: 'I feel very emotional about it because I always felt that one of his great strengths was his Christian faith.'

While Catholic church leaders welcomed him, other Catholics were likely to greet the news with 'raised eyebrows', said Catherine Pepinster, editor of the Catholic newspaper the Tablet. These would include those who had disagreed with his policies on Iraq, and those who believed him to be a man with a voting record in favor of abortion, she said.

Blair always avoided talking about his religion while in office for fear of being labeled 'a nutter', he admitted in one BBC interview, while confessing that his faith had been 'hugely important' to him. In one rare departure, he did admit that he had prayed to God when deciding whether to sent British troops to Iraq.

Behind the scenes, however, his aides always had to find him a church to attend wherever he was on a Sunday, and the EU Trade Commissioner, Peter Mandelson, a close confidant of the former Prime Minister, said he took a Bible with him wherever he went to read at night.

Former Conservative minister Ann Widdecombe, who converted to Catholicism in 1993, said Blair had gone against church teachings on more than one occasion: 'The crucial thing to remember is at the point you are received [into the Catholic church] you have to say individually and out loud: "I believe everything the church teaches to be revealed truth."

'That means if you previously had any problems with church teaching - as Tony Blair obviously did over abortion, as he did again over Sunday trading - you would have to say you changed your mind,' she told Sky News.