THE North-East priest who baptised Tony Blair's children says the outgoing prime minister's likely conversion to Catholicism comes as no surprise to him.

Father John Caden, a close family friend of the Blairs, said a decade in Downing Street had made it difficult for the prime minister to be open about his spiritual faith.

Asked if he expected a conversion once Mr Blair steps down in four days' time, Father Caden replied: "It would not surprise me at all - it takes that problem away."

The priest, who said mass for the Blair family at his tiny St John Fisher Church, in Sedgefield, until the mid-1990s, spoke ahead of the prime minister's expected visit to the Vatican today. (Sat).

Downing Street announced last month that Mr Blair would make a final visit to Benedict XVI before leaving office, because he was keen to "discuss interfaith issues".

However, it is increasingly believed he has taken the decision to seek admission to the Catholic church, with an announcement possible next week.

Father Michael Seed, who has said mass for the Blairs in Downing Street, has said the prime minister is ready to declare his switch from Anglicanism.

Cherie Blair and the couple's four children are Roman Catholic. Furthermore.

Mr Blair was once criticised by the Archbishop of Westminster for taking communion at his wife's church in North London.

However, Britain has never had a Catholic prime minister, a situation which, it is suggested, would create problems over the appointment of Church of England bishops.

Father Caden, speaking to the Northern Echo, suggested a conversion would also have made it more difficult for Mr Blair to achieve a peace settlement in Northern Ireland.

And he added: "The prime minister is an Anglo-Catholic, who has brought his children up in the Catholic faith better than any Catholic father could have.

"But ten years in office hasn't helped, because we are talking about him making a personal, private decision about his spiritual life.

"He has taken enough brickbats without talking about his spiritual life to the world. It would not surprise me at all if he converted, because that won't be a problem now."

Father Caden, who also used to play tennis regularly with Mr Blair in the 1980s and 90s, added that the future prime minister never spoke to him about conversion during those years.

Ahead of today's Vatican visit, Mr Blair was plunged into a a fresh 'freebie' row when it emerged he will stay at Chequers, the country retreat of prime ministers, after quitting Downing Street.

Builders are still refurbishing the Blairs' £3.6m Georgian townhouse in North London and he is thought to have ruled out Myrobella, his Sedgefield home, as too distant from London.

Downing Street said there was "a tradition" that outgoing prime ministers were given two or three days to collect their belongings and say goodbye to the staff at Chequers.

But Grant Shapps, vice-chairman of the Conservative party, said: "Tony Blair will effectively be living in a huge country estate at the taxpayers' expense."

Meanwhile, a United Nations spokeswoman has confirmed that a proposal for Mr Blair to become a Middle East peace envoy after leaving office was "under discussion".

This week, the White House indicated that President George Bush and Mr Blair had discussed the possibility and the move has been backed by Israeli Prime Minister Ehud Olmert.