Religion should not play the same role in British politics that it does in America, Tony Blair has said.
Tony Blair is a member of the Christian socialist movement
Mr Blair said he did not want a system where politicians went out "beating their chests about our faith".
The prime minister was speaking to a Christian group already addressed by the Tory and Lib Dem leaders.
During a questions session, he warned that "we are piling up problems for the future" when inner city women start families when "very, very young".
"It is important that they get role models at school and in the community, where they see it is not a great life, trying to bring up a single parent family aged 17 or 18 - actually it is pretty miserable," he said.
Downing Street later insisted Mr Blair did not want to blame any particular group for the ills of society.
'Don't do God'
Mr Blair was speaking to church leaders, other faith representatives and community activists in London about his vision for the role of faith in the UK.
The lecture was organised by the Faithworks Movement, which hopes faith will be a hotly contested election issue.
In the questions session after his speech, Mr Blair was asked about reports that Alastair Campbell had once told an interviewer who asked about Mr Blair's faith: "I'm sorry, we don't do God."
Mr Blair said faith was very important on a personal level but could quickly become misinterpreted.
"I don't want to end up with an American-style type of politics with us all going out there and beating our chests about our faith," he said.
People were defined by their faith but it was "a bit unhealthy" if it became used in the political process.
Tuesday's lecture comes after both the Anglican archbishop of Canterbury and the Roman Catholic archbishop of Westminster suggested abortion should be an election issue.
In his speech, Mr Blair said a vision of community, with people helping each other, was central to his politics.
He said churches made a "visible, tangible difference" for the better in society.
"I would like to see you play a bigger, not a lesser, role in the future," he said.
"So many of your organisations have the capacity not only to help, but to inspire and to enthuse, by being unashamed about your beliefs, your commitment and your example."
Mr Blair said he wanted to "recast" the 1945 welfare state for the modern age.
But governments could only do things in partnership with others, including faith groups who were helping the "millions" of young people who failed to fulfil their potential.
He also praised churches for being at the forefront of attempts to fight world poverty and injustice.
In his speech to Faithworks, Mr Howard said faith groups were part of a "forgotten majority" and needed a fairer deal for their social work.
Lib Dem leader Charles Kennedy told the group that fears of fundamentalism should not prevent local councils from trusting churches.