A Belfast High Court judge has quashed a decision made by former direct rule Minister Lord Rooker which effectively banned one-off housing in Northern Ireland's countryside.
Mr Justice Gillen ruled that the decision of the minister was both unlawful and beyond Mr Rooker's powers.
The judicial review found that the legislation should have been brought in by the Department of the Environment rather than the Department for Regional Development.
The judgment, following a legal challenge taken by Omagh District Council, will now put pressure on the new devolved government at Stormont to bring in fresh laws.
Several thousand applications for one-off housing in Northern Ireland will now have to be re-examined by Environment Minister Arlene Foster.