Leading judges are to announce their decision on a Government challenge against a ruling that its controversial benefit cap unlawfully discriminates against lone parents with children under two.
The Court of Appeal's announcement on Thursday follows a High Court action last year which concluded with a judge saying that "real misery is being caused to no good purpose".
Mr Justice Collins ruled in favour of four lone parent families in their action against the Work and Pensions Secretary over the benefit cap, which limits the income households receive in certain benefits.
He said the successful claim related to the "revised" benefit cap which "requires the parent in order to avoid the imposition of the cap to work at least 16 hours per week".
But, at the Court of Appeal in October last year, lawyers for the Work and Pensions Secretary urged three judges to overturn his decision.
Clive Sheldon QC, for the Government, told Sir Brian Leveson, Lord Justice McCombe and Sir Patrick Elias that the judge had made "a number of serious errors", adding: "But for those errors, the claim would have been dismissed."
Mr Justice Collins was "wrong and erred in law in determining on the evidence before him that the benefit cap unlawfully discriminated" against the claimants who brought the action.
Mr Sheldon submitted there was "no discriminatory impact and, in any event, any such impact would be justified".
Lawyers for the families have asked the appeal judges to dismiss the Government's challenge.
They said that a reduced benefit cap, introduced in 2016, "drastically reduced housing benefits, leaving lone parent families across the country unable to afford basic life necessities to care for their children".
Mr Justice Collins said the regulations were "unlawful insofar as they apply to lone parents with a child or children under the age of two", as they involve "unjustified discrimination" against parents and children.
In his ruling, he said: "Whether or not the defendant accepts my judgment, 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.
"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."