A man has successfully challenged a benefit cut under the so-called "bedroom tax" after a QC ruled that spare rooms must be a minimum size to qualify.
David Nelson, 57, contested a reduction in his housing benefit over a "box room" measuring 66 sq ft at his home in Glenrothes, Fife.
He received a letter saying that a room measuring between 50 and 70 sq ft was suitable as a bedroom for under 10s only, while a room with an area of less than 50 sq ft could not be considered a bedroom at all.
The response came from QC Simon Collins, who was appointed by the Government to judge "bedroom tax" tribunals, the Courier newspaper reported.
Under new welfare reforms, social tenants deemed to have more bedrooms than they need have had their housing benefit reduced since April.
Ministers say it tackles an unfair ''spare room subsidy'' not available to private-sector renters and suggest it will save around £500 million annually as part of the deficit-reduction strategy. But it has sparked protests across the country, with critics claiming it is forcing families into poverty.
Mr Nelson's appeal follows unsuccessful challenges to the policy in Birmingham earlier this year.
He lives with his wife in a three-bedroom property and had already successfully appealed to the local authority that his second bedroom was often used by his son, who acts as his carer. He told the Courier: "The letter I got said a room of 66 sq ft can only be used by a child up to 10 years old. It can't even be used by a lodger because it's too small."
The paper said that although the findings will be used as guidance to future tribunal judges and local authorities, they are not legally binding. Fife Council is said to be considering the ruling, against which it has the right to appeal.
Scotland's Deputy First Minister said the ruling could be of "huge significance" and underlined existing concerns that the policy breached human rights.