Mr Blair has taken Catholic Communion

The prime minister, an Anglican, had reportedly expressed an interest in joining his wife Cherie and their four children in the Catholic faith.

The Blair family priest, Father Timothy Russ, told The Times newspaper Mr Blair "may well" convert.

But Mr Blair emphatically denied the story when challenged by reporters, joking: "Don't they run this once a year?"

'No barrier'

Fr Russ, the priest who presides over communion at Chequers, said it would be "unwise" to speculate on whether Mr Blair would convert but added "it might well end up that way".

Mr Blair had even asked him: "Can the prime minister of Britain be a Catholic?," he told the paper.

But asked by reporters in Budapest, where Mr Blair is attending a Progressive Government conference, whether he was planning to convert, he said: "I am saying no.

"Don't they run this once a year? I think they do."

In his interview with The Times, Fr Russ criticised the government's handling of issues such as pensions, saying Mr Blair was a "lazy thinker when it comes to certain ethical questions."

In the run-up to the Iraq war, Mr Blair had a private audience with the Pope in the Vatican.

He also worships at Catholic churches with his family and this summer took his first Catholic communion in public for seven years while staying in Italy.

There has never been a Roman Catholic prime minister of Britain, although there is no constitutional barrier to such a move.