A much-hyped Labour revolt over the pounds 400m cut in lone parent child benefit is expected to attract no more than two dozen backbench rebels in the Commons next Wednesday.
All the rebels are expected to abstain rather than vote with the Tories on the remaining stages of the Social Security Bill, and in an interview with The Independent last night Ms Harman reassured critics that the lone parent cut is a one-off - and will not create a precedent.
"I don't want people to see this as a carrot-and-stick approach," she said. "I have never thought that lone parents needed to be given an incentive of a benefit reduction to work. But we do need to stay within our budget, and it is unavoidable."
Ms Harman said: "This is an inheritance measure, left over by the Tories. It is not part and parcel of the New Deal. I left no stone unturned to see whether it was unavoidable."
She added that there was no question of the cut being applied as a principle or precedent. "Absolutely not," she said. "It is not a principle. I don't believe in cuts in lone mothers' benefit to drive lone mothers into work. I believe in making work pay. They don't need encouragement; they need opportunity. They want to work, they want to be better off, and they want their children to be better off."
The latest departmental surveys were showing that of those lone mothers who were being interviewed under the New Deal approach, designed to assist lone mothers into work, four out of every five wanted work and wanted to keep looking for work.
Ms Harman, who will be addressing a meeting of senior managers today about her zeal for the New Deal, said Labour's approach was to build on the enthusiasm of people who wanted to help themselves. "The Tories were absolutely blind to it," she said. "They didn't even count them as unemployed, more than half the workless households.
"They were able not to notice a million sparky, enthusiastic, motivated and well- organised lone mothers.
"They were not able to see those people with some disabilities or health problems who, with a bit of extra help and support, would actually be doing a job, and wanting to be."
But in a later Commons intervention, the Labour MP Dennis Skinner criticised some of the language of Labour's New Deal approach, saying that there were villages in his Bolsover, Derbyshire, constituency where pit closures had left thousands out of work.
"I want the ministers of this Government to understand that there are areas of Britain, including mine, where this idea of work being available is laughable for a lot of people," he said.
In a Commons written reply last night, Ms Harman announced a pounds 2.45bn benefits uprating for 1998-99.
She said the key points of the uprating, which included an inflation- based increase of 3.6 per cent for all National Insurance benefits, included a pounds 2.25 rise in single pension, to pounds 64.70, with an extra pounds 3.60 for pensioner couples, taking their pension to pounds 103.40 from the week starting 6 April 1998.
On child benefit, she said: "The rate for the eldest child will be increased to pounds 11.45. The rate for each subsequent child is increased to pounds 9.30."