The government is to identify at risk children in the womb, as part of a bid to tackle the 'hardcore' vestiges of social exclusion.
A Downing Street review recommended unborn babies at risk of social exclusion and anti-social behaviour are identified at 16 weeks gestation and their mothers offered intensive support.
Women would be visited weekly by a midwife or health visitor until their child is two. They will help first-time mothers bond with their babies and develop their parenting skills, as well as providing practical help to quit smoking or drug use.
The prime minister Tony Blair said such action is needed to help the 'hardcore' two to three per cent of socially excluded families who have not benefited from existing government efforts.
He argued the government must be prepared to target children before they are born. Supporters of the scheme claim the risks of stigmatising the child are outweighed by the benefits intensive support can bring.
The policy follows a similar trial in the US. There, the Nurse Family Partnership showed positive results, with improved IQ skills and language development, lower levels of abuse and neglect and improve antenatal health and job prospects for young mothers.
The scheme will be voluntary but it is hoped young parents will be receptive to the support.
Mr Blair argued such intensive support is necessary to help break the cycle of deprivation and anti-social behaviour. He repeated arguments that a general focus on marriage fails to benefit the most socially-excluded.
Conservative calls for tax breaks for married couples risk discriminating against children when their parents split up, the prime minister warns. Instead he will call on his successor to target resources on a small minority of fractured families.
Labour and the Conservatives are beginning to show a clear policy divide over the state's role in family life, with the Tories reiterating calls for tax breaks for married couples.
Continuing his leadership campaign today, Gordon Brown will refute their argument. On a visit to Manchester he will defend the current tax credit scheme, which the chancellor claims targets help at the most needy families.
He will also propose teenagers at risk of dropping out of education are assigned mentors and spend one day a week training in the workplace.
Meanwhile, the Conservatives have accused Mr Brown of failing to support families awaiting payments through the Child Support Agency (CSA).
The shadow work and pensions secretary Philip Hammond claims 1.4 million families have been "let down" by the CSA and called for changes to the maintenance payments system to be fast tracked.
He said: "The proposed new system won't be fully up and running until 2013. What are families stuck in the nightmare of the CSA supposed to do until then?
"Gordon Brown is clearly trying to draw a line under the current CSA fiasco so he can begin his premiership with a clean sheet. But the families who are being failed by the current system will continue to suffer for years."