The former Fine Gael minister, Mr Michael Lowry, has been given permission by An Bord Pleanala to retain the large extension to his Co Tipperary home which was paid for by Mr Ben Dunne and built without planning approval.
The board rejected an appeal by Lancefort Ltd - a company set up by Dublin-based conservationists to fight important planning cases - against North Tipperary County Council's decision to grant retrospective permission to Mr Lowry.
The appeals board said it considered that the alterations to the house at Glenreigh Beg, Holycross, "reflect and respect the character of the original dwelling and harmonise with it" and also that the new entrance was "acceptable in terms of traffic safety and convenience".
Mr Michael Smith, a director of Lancefort, said the decision seemed to take no account of the fact that Mr Lowry's planning application was retrospective. "In fact, the board doesn't concern itself with legalities at all.
"This highlights an anomaly under the planning laws whereby there is really no incentive to apply for planning permission before you start developing, because even if the local authority ever discovers you are in breach of requirements, you can always apply for retrospective permission," he said.
Asked why Lancefort had taken the case to the planning board, Mr Smith said it was "a particularly flagrant flouting of the law by a man in a position to know better", highlighting "a major flaw in the planning Acts".
Since Lancefort lodged its appeal four months ago it had been "inundated with calls from people nationwide with their own particular complaints about the failures of local authorities to enforce the planning laws". These were running at a telephone call per day.
Last year, Mr Smith said, Dublin Corporation alone had a backlog of 1,200 planning enforcement cases and he had no reason to believe that this had been reduced since then.
At present, Lancefort is involved in a major High Court action challenging the validity of An Bord Pleanala's decision to grant planning permission for the controversial Hilton Hotel proposed for the edge of College Green, in Dublin.
