“Many desperately want to work but can’t make up the required hours of work a week due to childcare issues or insecure work like zero-hours contracts.”But the Department for Work and Pensions immediately announced it intends to appeal against the ruling.A spokesman for the department said: “We are disappointed with the decision. Work is the best way to raise living standards, and many parents with young children are employed.”The benefit cap incentivises work, even if it’s part-time, as anyone eligible for working tax credits or the equivalent under Universal Credit, is exempt.”Even with the cap, lone parents can still receive benefits up to the equivalent salary of £25,000, or £29,000 in London [£20,000 and £23,000 after deductions], and we have made Discretionary Housing Payments available to people who need extra help.”The DWP added that since the introduction of the cap in April 2013, over 29,000 households who previously had their benefits capped have moved into work and are no longer capped. Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings. A central plank of the Government’s benefit reform programme has suffered a major setback after a High Court judge ruled it was unlawful and was causing “real misery” to single parents and their children.Four single parents yesterday won their case against the use by Ministers of the controversial ‘benefit cap’ to limit the amount of benefit they receive.Campaigners had argued that the cap forced single parents with children under two into poverty and homelessness, leaving them to rely on food banks and handouts.The cap of £20,000, or £23,000 in London, is imposed on benefits received by those not working at least 16 hours a week.But the single parents who took the Work and Pensions Secretary to court, on behalf of as many as 17,000 families, claimed it discriminates against the most vulnerable in society, who frequently struggle to pay for child care or are in zero-hours contracts.Mr Justice Collins ruled in favour of their claim that they and their dependant babies and toddlers should have been exempted from the scheme.He said: “The evidence shows that the cap is capable of real damage to individuals such as the claimants. They are not workshy but find it, because of the care difficulties, impossible to comply with the work requirement.” The judge added: “Most lone parents with children under two are not the sort of households the cap was intended to cover and, since they will depend on DHP (Discretionary Housing Payments), they will remain benefit households. Real misery is being caused to no good purpose.”Following the ruling the Government said it would await the outcome of an appeal to a higher court before deciding whether to grant an exemption to the cap for lone parents with children under two, allowing them to receive potentially hundreds more in annual benefits.Mr Justice Collins’ ruling is being interpreted as a significant victory by the Government’s opponents, with Labour leader Jeremy Corbyn saying the benefit cap represented another failing of the austerity programme.He said: “It is failing in its own terms, it’s failing our communities, and it’s failing the most vulnerable in our country – including the victims of domestic violence and those facing homelessness.”The Prime Minister should accept the High Court’s judgment and end this discrimination against parents and children.”Lawyers for the four one parent families said the judge had ruled that the application of the cap was unlawful because of its discriminatory impact on lone parents with children under two. Rebekah Carrier, of Hopkin Murray Beskine Solicitors, said: “The benefit cap has had a catastrophic impact upon vulnerable lone parent families and children across the country.”Single mothers like my clients have been forced into homelessness and reliance on food banks as a result of the benefit cap.”Thousands of children have been forced into poverty, which has severe long-term effects on the health and well-being.”She added: “We are pleased that today’s decision will relieve my clients – and other lone parent families around the country – from the unfair impacts of austerity measures which have prevented them from being able to provide basic necessities for their children.”Charities have also welcomed the ruling against what they said was a “nasty policy”.Alison Garnham, chief executive of the Child Poverty Action Group, said: “In exposing the absurdity and cruelty of the benefit cap, we hope this case is the beginning of the end for this nasty policy. It is a policy that punishes the vulnerable for being vulnerable and even fails on its own terms.”Anne Baxendale, director of communications, policy and campaigns at homelessness charity Shelter, which supported the challenge, said: “Many of the families that come to Shelter for advice say the benefit cap is pushing them into homelessness.