Single parents will lose up to £60 a week following delays to the Government's flagship welfare reform, it has been disclosed.
Their income will be slashed because of the cancellation of In Work Credits, a payment to single parents and some couples who move into jobs.
The credit, which was worth £40 a week to people outside London and £60 to those living in the capital, was scrapped in October for new claimants.
The cancellation was timed to coincide with the planned national roll-out of the Universal Credit scheme.
Universal Credit, which replaces six benefits and tax credits with a single payment, has been hit by delays and is currently only paid through a handful of jobcentres. A revised timetable for its introduction is due to be announced within weeks.
Chris Bryant, the shadow Work and Pensions Minister, said: “Ministers say there is no need for In Work Credit because of Universal Credit. But that is now massively delayed with the Tory-led Government unable to say when it will be available right across the country.
"Families facing a cost-of-living crisis and trying to get back to work deserve better."
The Department for Work and Pensions said In Work Credits, which were launched in 2008, created a perverse incentive not to work as they were only open to claimants once they had been on benefits for a year.
A spokesman said: "Under Universal Credit, people will get the help they need earlier to move into a job. We are determined to help more lone parents take their first steps into work.
“That is why lone parents now get more help and earlier help from Jobcentre Plus to move off benefits with advisers giving one-to-one advice on support including training, childcare, and job applications.”