Hundreds of drivers summonsed for speeding in Co Kildare look set to have their cases dismissed.
This follows the disclosure that speed limits between Athy and Kilcullen are "unauthorised".
Although Kildare County Council erected signs indicating that motorists should not exceed 40 miles an hour, it is being claimed they have no legal status.
The information was revealed during a debate at a meeting of Kilkenny County Council.
Solicitor Michael Lanigan, a member of the Kilkenny council, was told that although Kildare County Council had erected the signs, they had not received permission to do so from the National Roads Authority (NRA).
For that reason the speed limit signs were "unauthorised".
Mr Lanigan said after the meeting that it could lead to the quashing of hundreds of convictions for speeding and the dismissal of many such cases still to be heard by the courts.