Labour believes the move -which Mr Blair will unveil in his speech to the party conference - is an important extension of his commitment to a "welfare into work" programme. Party strategists believe that it will be electorally popular, including among lone parents themselves.
The plan is closely modelled on the successful Australian Jobs Education and Training Programme which was launched by Paul Keating's Labour government.
Unpublished Department of Social Security research shows that 90 per cent of single parents would take paid work if they could.
The new plan, which reflects Mr Blair's commitment to an "active rather than passive welfare", will require the Benefits Agency to draw up employment- and child-care plans for lone parents with children over five, rather than merely continue to pay them benefits such as income support. Australian experience suggests that the scheme would save money.
Only 40 per cent of British lone parents are in work - the third lowest level in the EU. A quarter of children have parents who are divorced.
The move will come as part of the unwrapping of a series of specific policy pledges this week in Brighton, starting today with Labour Treasury spokesman Gordon Brown's announcement of details of his pounds 1.4m youth employment programme, to be financed by a windfall tax on the privatised utilities.
In addition to the plan to reintegrate lone parents into the labour market, the Labour leader will announce plans for a pounds 110m scheme to reduce primary class sizes. It will be financed by scrapping the assisted places scheme for state funded pupils to go to private schools.
Party strategists are optimistic that it will overshadow debate over a series of divisive issues, which threaten to dominate the conference.
The most immediately fractious is the National Executive's decision to withhold endorsement from Liz Davies, the left-winger chosen as parliamentary candidate for Leeds North East.
The executive yesterday agreed to allow a short conference debate on the issue by agreeing to submit a short report on their decision to delegates tomorrow morning.
But in a move that may be challenged on the conference floor today, the conference organisers refused to accept 13 emergency motions demanding her immediate reinstatement.
In an interview with the Guardian, Mr Blair says that people like Ms Davies had a choice: "They've got to decide if they're going to help a Labour government or carry on in a narrow sectarian politics that has no popular resonance. If they stood on the Labour Briefing platform they'd get 500 votes. If they want to stand on my policies and my back, in order to get into power to cause trouble for a Labour government, I think we're entitled to say no to that."
The leadership's chances today of defeating a highly embarrassing motion demanding Labour commit itself to a a minimum wage of pounds 4.15 suddenly improved yesterday, when the Transport and General Workers' Union bowed to intense pressure behind the scenes and agreed not to support the call.
But the GMB general union last night was holding out in support of the motion, which cuts across Mr Blair's determined insistence that Labour cannot to commit itself to a figure before the election and should instead leave it to a Low Pay Commission. If the Edinburgh Central Constituency, which proposed the motion, insists on pressing it to a vote, the result is likely to be close.
Aides to Mr Blair, who provoked anger within the party by sending his son, Euan, to an opt-out school, are bracing themselves for a highly-charged debate over grant-maintained schools on Wednesday.Reuse content