Permission for a housing project in the Ring Gaeltacht in Co Waterford has been overturned by An Bord Pleanála.
The decision is a victory for a local residents' group which claimed the 22-house scheme at Baile na nGall would have opened the door to suburban-type development in the area.
That view was rejected by Waterford County Council, which granted permission for the scheme to Mr Seán Halpin, from Waterford, in June.
An Bord Pleanála said the scheme would set a precedent for similar developments and would dilute the area's Gaeltacht status. It said the site was in an elevated and exposed position, with extensive views over Dungarvan Bay, Ring and the Helvick peninsula.
The scheme "would constitute an extremely obtrusive element in the landscape" and "would seriously injure the visual amenities of the area", it said.
"The proposed development, by reason of its nature and scale, would be a considerable diluting element within a Gaeltacht area which is both culturally and environmentally sensitive, would diminish the visual amenity and rural character of the area and create a precedent for similar development proposals unrelated to the needs of the existing community settlements."
The decision was welcomed by Mr Mick Ó hUallacháin, a member of Gaeltacht i mBaol (Gaeltacht in Danger), which campaigned against the development. The group had been vindicated as "ordinary people" who had spent the past 18 months fighting Waterford County Council's planning section.
Mr Fiachra Ó Céilleachair, a Labour county councillor and member of Údarás na Gaeltachta, said the bord's decision would ease fears that Ring would undergo the type of radical transition made possible by an action plan for the area adopted by the council last year.
The plan allows for developments with a density of between three and eight houses an acre. Mr Ó Céilleachair says single site and smaller scale developments, subject to the normal planning conditions, are more appropriate for the area.
"The planning arguments against what the county council had in mind for Ring are not just mine or Gaeltacht i mBaol's any more. An Bord Pleanála is arguing that the nature and scale of something like the Baile na nGall development was not suitable for the area."