The former Prime Minister Tony Blair has been received into the Roman Catholic Church.

Mr Blair was received into full communion with the Catholic Church by Cardinal Cormac Murphy-O'Connor, Archbishop of Westminster, during Mass in the chapel at Archbishop’s House, Westminster, on Friday.

Mr Blair, formerly a member of the Church of England, has been receiving doctrinal and spiritual preparation from Mgr Mark O’Toole, the Cardinal’s private secretary.

Cardinal Murphy-O’Connor said: 'I am very glad to welcome Tony Blair into the Catholic Church. For a long time he has been a regular worshipper at Mass with his family and in recent months he has been following a programme of formation to prepare for his reception into full communion. My prayers are with him, his wife and family at this joyful moment in their journey of faith together.'

His conversion follows months of speculation. As long ago as May, The Times reported exclusively that he was intending to become a Catholic after he left Downing Street.

Political and interdenominational sensitivities meant he felt unable to follow his spiritual heart's desire while in office.

He was once chastised by the former Archbishop, the late Cardinal Basil Hume, for receiving communion alongside his Catholic wife Cherie and his children at their former church in Islington. Inter-commununion is banned by the Catholic Church although permitted by Anglican bishops.

There were also fears among his advisers about his being identified publicly as a devout Christian. Even though his faith and personal leanings towards Catholicism have never been a secret, his former press secretary Alastair Campbell once famously said: 'We don't do God.'

The reception of baptised Christians into the Catholic Church is a liturgical rite by which a person who is already baptised is received into full communion. The rite normally takes place within the celebration of Mass. A baptised Christian who wishes to become a Catholic receives doctrinal and spiritual preparation adapted to individual pastoral circumstances.

A pastoral discernment is made regarding the length of catechetical formation required for each individual candidate for reception. The rite involves making a profession of faith.

It is part of the office of the diocesan Bishop to ensure that those to be received are properly formed and welcomed into the Catholic Church.

Before the profession of faith and reception the candidate make a confession of sins. They are asked to inform the confessor that they are to be received into full communion. At the reception a candidate is accompanied by a sponsor.

There has been public speculation about whether Mr Blair's confession would include any reference to the war in Iraq, or to Parliamentary policy on 'life' issues during his time as Prime Minister.

Read Ruth Gledhill's blog on the Blair conversion