A separated father of three has won his Supreme Court case over Dublin City Council's categorisation of him as a one person household on its housing list.
The decision could have implications for more than 800 separated people in similar situations on the Council's housing list.
The City Council must now reconsider the man's situation in line with the court's findings.
The man's children stay with him for three nights of the week in his one bed apartment and spend the remainder of the week with their mother in a larger property.
He gets the Housing Assistance Payment at a single person's rate of €990 a month while his former partner gets a larger HAP payment because she's a separated mother.
The man had challenged the City Council's determination after his separation in 2017, that his housing need was for a one bedroom unit. He claimed the council was operating an unfair, irrational and discriminatory housing scheme by classifying separated fathers as "single" when allocating housing.
His case was rejected by the High Court. But the five judge Supreme Court unanimously found in his favour.
However, the decision does not necessarily mean the man or others in a similar situation will be entitled to housing accommodating their children, because the Council is entitled to prioritise housing based on greatest need.
The appeal centred on the interpretation of the word "household" under the relevant legislation.
Giving the court's judgment, Ms Justice Mary Irvine said the appeal was primarily about how a housing authority should lawfully conduct assessments under the relevant section.
The assessment was based on the "reasonable requirement to live together" and the council was entitled to inquire into the circumstances of the applicant and those with whom they want to live.
The judge said the council's opinion on the requirement of people to live together should be based solely on their requirements and resource considerations should not be factored in at this stage.
She said classifying a parent as a one person household on the basis that their children were provided for by the other parent's household was a "de facto" blanket policy on the council's part. It prevented any case by case assessment.
Ms Justice Irvine said council documents had described parents like the man as "access" parents, when in many cases they were nothing of the sort and were joint custodians of their children, entitled to have a significant role in their upbringing.
The judge said however, that the council was not to be faulted for taking the position that it could not allocate two separated parents two houses with accommodation for the children when bedrooms were vacant half the time, while other children on the housing list had no accommodation at all.
She said even if the council decided this man had a reasonable requirement to live with his children, he might find his household is "close to the bottom" in terms of priority.
She said it was not only permissible, but just, that the council should prioritise households in greatest need when deciding on the allocation of housing stock, while the country was "in the throes of a crippling housing crisis".