A separated father of three with joint custody and access rights has won a key Supreme Court appeal over Dublin City Council's categorisation of him on its housing list as a one-person household.

The council must now reconsider the man's application in line with the court's findings, including the council is not entitled to operate a "blanket" policy towards such persons but must assess their individual circumstances.

The five-judge court's unanimous judgment has implications for more than 800 separated persons in similar situations on the Council's housing list who were treated as single-person households, meaning a lower Housing Assistant Payment (HAP), after their former partner was categorised as a larger household with a larger HAP.

However, the judgment does not mean either the man or others in a similar situation will be entitled to housing accommodating their children because the council remains entitled to prioritise housing according to greatest need.

Certain other councils apply a different policy to separated persons with custody/access rights, the Supreme Court noted.

After judgment was delivered today, Feichín McDonagh SC, with Brendan Hennessy BL, instructed by Eileen McCabe, for the man, obtained orders quashing the council's decision and remitting the matter for reconsideration.

The man had secured a Supreme Court appeal, on the basis his case raised issues of general public importance, after the High Court rejected his case.

The Irish Human Rights and Equality Commission was involved as an amicus curiae, assistant to the court on legal issues.

The Attorney General got involved at a late stage to argue there is no unenumerated right to housing and disputing any breach of child and family rights.

The right to housing ultimately did not become an issue and the appeal centred on interpretation of "household" under section 20.1 of the Housing (Miscellanous" Provisions Act 2009.

Section 20.1 defines “household” as a person who lives alone, two or more persons living together and two or more persons who do not live together but who, "in the opinion of the housing authority, have a reasonable requirement to live together”.

The children stay with their father three nights weekly in his one-bed apartment and spend the other four nights with their mother in a larger unit. He gets €990 monthly Housing Assistance Payment (HAP), a single person's rate, while she gets a larger HAP as a separated mother.

Giving the court's judgment, Ms Justice Mary Irvine stressed the appeal was primarily about how a housing authority should lawfully conduct assessments under section 20.1.

That assessment is based on an "objective yardstick", the reasonable requirement to live together, and the council is entitled to interrogate the personal circumstances of the applicant and those with whom they want to live.

The council's opinion regarding the requirement of persons to live together must be based solely on the requirements of those persons and resource considerations could not be factored in at this stage of the process.

To classify every parent as a one-parent household on foot of resource considerations on the basis their children are already provided for as part of the household of the other parent constitutes a "de facto" blanket policy on the council's part, she held.

Such a policy was outside the terms of section 20.1 because it prevented any case-by-case assessment in such cases and meant, regardless of their rights and desires as joint custodians of their children, their requirement to live with their children would be automatically assessed as "objectively unreasonable".

Council documents had described parents like the man as "access" parents when, in many cases, they were "nothing of the sort" and were rather joint custodians of their children wishing to have, and entitled to have, a significant role in their upbringing.

The courts are seeing more and more joint parenting agreements, she added.

The council, she noted, is sensitive in its efforts to ensure those with the greatest housing needs are prioritised.

It was "not to be faulted" for taking the position, where housing need greatly exceeds available resources, it cannot allocate to two separated parents two houses with accommodation for the children when bedrooms would be vacant for half of the time and other children on the housing list have no accommodation at all.

If the council decides this father has a reasonable requirement to live with his children, he might find his household is "close to the bottom" of its list in terms of priority.

While the council cannot take housing resource issues into account in considering how to categorise the man's housing need, resource issues can be considered later when the council is determining allocation of housing, she said.

Section 22 of the 2009 Act makes clear the council can allocate its housing stock according to available resources and on the basis it "can prioritise those most in need".

The entitlement to do so is "clearly vital given that the country is in the throes of a crippling housing crisis" with a greater than ever demand for social housing.

It is "not only permissible but just" that the council should prioritise those households with the greatest need.

While her conclusions meant it was not necessary to address child and family rights issues, she said the court's interpretation of section 20.1 would "undoubtedly be consistent" with the rights, "if any", as espoused in Article 42A of the Constitution and Article 8 of the European Convention on Human Rights.