The Government's free childcare policy is being challenged in the High Court by lone parents and their children, who say they are discriminated against.
Free childcare provision for three and four-year-olds whose parents are "deemed to be in work" was doubled from 15 to 30 hours from last year.
But in a legal action brought by three single mothers and their young children, it is argued the new rules discriminate against lone parents who are carers and those who have fled domestic violence.
All three are entitled to 15 hours of childcare, but cannot take advantage of the extended provisions because they do not have a partner who is in work.
The court heard on Thursday that one of the women is a full-time carer for her disabled mother, another cares for her two disabled children and the third is in a women's refuge, having fled from a violent husband.
Both women who act as carers are in receipt of carers' allowance and all three receive benefits, but are unable to afford private childcare.
One of the women is university educated and hopes to return to work, but is currently unable to because of her caring responsibilities.
The claimant, who is currently living in a refuge also wishes to return to work, but her living situation means it is "not feasible" at the moment, the court heard.
Ian Wise QC, representing the women and their children said the exclusion of the claimants from the 30-hour entitlement was an "unjustified discrimination".
He told the court: "It is apparent from the above that the child claimants are starting life from a position of very substantial disadvantage.
"They have no relationship with their fathers and their mothers are all dependent on state benefits.
"Their mothers face the additional challenges of providing care for the child's grandparent, sibling or fleeing domestic abuse.
"The substantial benefits that they would derive from the provision of additional free education and childcare are self-evident."
Mr Wise argued the women's exclusion from the extended childcare provisions interferes with their rights under Article 14 of the European Convention on Human Rights - protection from discrimination - and asked the court for a declaration to that effect.
Their case is being brought against the Secretary of State for Education, Damian Hinds.
Lawyers representing Mr Hinds argued there was no unlawful discrimination involved in the policy.
Rory Dunlop, for the Secretary of State, said: "Fairness did not require the Government or Parliament to single out lone parent carers, or lone parent victims of domestic violence, and make them eligible for the additional hours whether they work or not, and ignore other families who may have analogous, or equally strong, reasons for not being in paid work."
He added: "A law which is intended to benefit those in paid work will inevitably draw distinctions between those in paid work and those not.
"There will always be some 'hard cases' on the wrong side of the line - eg, for sympathetic reasons.
"The sympathy which such hard cases generate does not demonstrate a breach of Article 14."
Mr Justice Lewis reserved his ruling on the case until a later date, saying he wanted to take time to consider the "important issues" raised.
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