The allowance disclosed by Kenneth Clarke, the Chancellor, will provide up to pounds 28 net a week from next October against child-care costs for single and two-parent families on family credit, disability working allowance, housing benefit and council tax benefit.
Such a scheme had been promoted by Gillian Shephard, Mr Hunt's predecessor, but had not been adopted because it was too expensive.
According to Whitehall sources, when Mr Hunt championed the idea he encountered little opposition from ministerial colleagues, chalking up a significant victory for the left in the Cabinet.
It was accepted despite advice from officials that it would be complex to administer and initially expensive.
Right-wingers had portrayed lone mothers as teenagers who got pregnant to get benefits and homes, or as responsible for rising crime. Treasury lobbying produced a commitment to spend about pounds 60m by 1996-97, with a net cost to the public sector borrowing requirement of pounds 30m.
Many lone parents are unable to take advantage of family credit - the benefit for low-income families in work or leave the benefit system, because paying child-care costs while working would leave them worse off than if they remained on income support.