Planning permission for a development of 657 apartments on a site connected to St Anne's Park in Raheny has been quashed by the High Court.
An Bord Pleanala consented to the High Court order on the basis it had not adequately considered the impact of the development on light-bellied brent geese and other protected bird species in Dublin Bay.
The planning application by developer Crekav, part of Pat Crean's Marlet group, will now be remitted to the board for a new decision.
This will be made "in accordance with law" from the time the board received a report last December from the chief executive of Dublin City Council (DCC).
The application must also be determined within 57 days of perfection of the High Court orders.
The DCC report had recommended permission be refused for reasons including that the developer had not demonstrated the project would not impact on the populations of protected brent geese, black-tailed godwits or curlews.
It considered the proposed development would materially contravene the Dublin City Development Plan objective for protection of European sites and would be contrary to the proper planning and sustainable development of the area.
Two separate challenges to the board's permission had been admitted to the High Court's Strategic Infrastructure Development list.
The board had indicated last month, in relation to the first challenge, brought by environmentalist John Conway, of St Nicholas Avenue, Dundalk, and the Louth Environment Group, represented by Stephen Dodd SC, that it was prepared to concede the case.
A second separate challenge to the permission was initiated by a local residents group, Clonres CLG, late last month.
Mr Justice Denis McDonald was told yesterday that there was consent to an order in both cases quashing the board's permission.
The judge made the consent order on the ground that the board did not conduct an appropriate assessment in accordance with the requirement of the Habitats Directive.
Both cases arose from the board's decision to grant permission for more than 650 apartments, in blocks up to nine storeys tall, to be built on former playing fields east of St Paul's College.
The proposal has been strongly opposed within the local community and by DCC.