The Government has been dealt a huge blow as the High Court ruled its benefit cap is unlawful and illegally discriminates against single parents with young children.

Conservative ministers are now likely to be forced to change or scrap one of their flagship welfare policies, which limits the total amount of benefits a household can receive to £23,000 a year in London and £20,000 elsewhere.

The ruling was made in response to a judicial review brought by four lone parent families who said the cap would have a severe and disproportionate impact on them.

Ministers had attempted to have the case thrown out but were rejected by the court, which ruled earlier this year that the case must be heard as a matter of urgency. The Government said it was “disappointed” with the latest ruling and will appeal against the decision.

Delivering his verdict, High Court judge Mr Justice Collins said the benefit cap was causing “real damage” to lone parent families, and, in a further blow to ministers, said “real misery is being caused to no good purpose”.

“Those in need of welfare benefits fall within the poorest families with children”, he said. “It seems that some 3.7 million children live in poverty and, as must be obvious, the cap cannot but exacerbate this. The need for alternative benefits to make up shortfalls is hardly conducive to the desire to incentivise work and so not provide benefits. There is powerful evidence that very young children are particularly sensitive to environmental influences. Poverty can have a very damaging effect on children under the age of five.”

“The cap is capable of real damage to such as the claimants. They are not workshy but find it, because of the care difficulties, impossible to comply with the work requirement. Most lone parents with children under two are not the sort of households the cap was intended to cover... Real misery is being caused to no good purpose.”

The most ridiculous reasons people had their benefits sanctioned Show all 16 1 /16 The most ridiculous reasons people had their benefits sanctioned The most ridiculous reasons people had their benefits sanctioned "One case where the claimant’s wife went into premature labour and had to go to hospital. This caused the claimant to miss an appointment. No leeway given" The most ridiculous reasons people had their benefits sanctioned "It’s Christmas Day and you don’t fill in your job search evidence form to show that you’ve looked for all the new jobs that are advertised on Christmas Day. You are sanctioned. Merry Christmas" The most ridiculous reasons people had their benefits sanctioned "You apply for three jobs one week and three jobs the following Sunday and Monday. Because the job centre week starts on a Tuesday it treats this as applying for six jobs in one week and none the following week. You are sanctioned for 13 weeks for failing to apply for three jobs each week" The most ridiculous reasons people had their benefits sanctioned "A London man missed his Jobcentre appointments for two weeks because he was in hospital after being hit by a car. He was sanctioned" 2011 Getty Images The most ridiculous reasons people had their benefits sanctioned "You’ve been unemployed for seven months and are forced onto a workfare scheme in a shop miles away, but can’t afford to travel. You offer to work in a nearer branch but are refused and get sanctioned for not attending your placement" 2013 Getty Images The most ridiculous reasons people had their benefits sanctioned "You are a mum of two, and are five minutes late for your job centre appointment. You show the advisor the clock on your phone, which is running late. You are sanctioned for a month" The most ridiculous reasons people had their benefits sanctioned "A man with heart problems who was on Employment and Support Allowance (ESA) had a heart attack during a work capability assessment. He was then sanctioned for failing to complete the assessment" Rex The most ridiculous reasons people had their benefits sanctioned "A man who had gotten a job that was scheduled to begin in two weeks’ time was sanctioned for not looking for work as he waited for the role to start" The most ridiculous reasons people had their benefits sanctioned "Army veteran Stephen Taylor, 60, whose Jobseeker’s Allowance (JSA) was stopped after he sold poppies in memory of fallen soldiers" 2014 Getty Images The most ridiculous reasons people had their benefits sanctioned "A man had to miss his regular appointment at the job centre to attend his father’s funeral. He was sanctioned even though he told DWP staff in advance" 2014 Getty Images The most ridiculous reasons people had their benefits sanctioned "Ceri Padley, 26, had her benefits sanctioned after she missed an appointment at the jobcentre - because she was at a job interview" Jason Doiy Photography The most ridiculous reasons people had their benefits sanctioned "A man got sanctioned for missing his slot to sign on - as he was attending a work programme interview. He was then sanctioned as he could not afford to travel for his job search" 2012 Getty Images The most ridiculous reasons people had their benefits sanctioned "Mother-of-three Angie Godwin, 27, said her benefits were sanctioned after she applied for a role job centre staff said was beyond her" The most ridiculous reasons people had their benefits sanctioned "Sofya Harrison was sanctioned for attending a job interview and moving her signing-on to another day" The most ridiculous reasons people had their benefits sanctioned "Michael, 54, had his benefits sanctioned for four months for failing to undertake a week’s work experience at a charity shop. The charity shop had told him they didn’t want him there" Getty The most ridiculous reasons people had their benefits sanctioned "Terry Eaton, 58, was sanctioned because he didn’t have the bus fare he needed to attend an appointment with the job centre" Getty Images

The claimants, two of whom have previously been made homeless as a result of domestic violence, had said the fact they had children under the age of two meant they were unable to work the minimum 16 hours per week that is needed in order to avoid the cap on their benefits. As a result, their welfare payments were cut.

Lawyers for the four families said they had been unlawfully discriminated against on the grounds they are single parents and therefore unable to work as many hours as other people. The review was supported by charities including Shelter, Gingerbread and Women's Aid.

Following the verdict, the families’ solicitor, Rebekah Carrier, 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.

“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.”

The Government immediately announced that it will appeal against the ruling and said it had been granted permission to do so.

A Department for Work and Pensions spokesman said: “We are disappointed with the decision and intend to appeal. 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 and we have made Discretionary Housing Payments available to people who need extra help.”

In 2015, the High Court deemed the benefit cap unlawful on the grounds that it discriminated against disabled people by not exempting their carers from the cap. As a result, ministers were forced to amend the policy to include an exemption for anyone in receipt of Carer's Allowance.