Motorists convicted of drink driving before March this year will not face new, longer driving bans which the minister introduced that month, the High Court has heard.
On March 5th, the Government extended the disqualification periods for convicted drink drivers.
In a controversial move, the then Minister for Transport, Martin Cullen, also stated that the extended disqualifications would apply retrospectively to all drivers banned at the time.
Francis Leeson, who was convicted of drink driving, challenged the retrospective element of the new penalties in a judicial review hearing before the High Court on Monday.
Leeson was convicted of drink driving, and had his application to restore his licence refused by District Court Judge John Coughlan on April 3rd, on the basis that under the new law the driver must serve a full two-year disqualification period.
During the hearing before Mr Justice Iarlaith O'Neill, counsel for the State, said the new disqualification periods apply only to those drivers "disqualified for more than two years", and as Leeson's driving ban was for exactly two years, the new rules did not apply to him.
As a result, he should have been allowed to apply for the early restoration of the licence under the old legislation, counsel for the State said.
The applicant's solicitor, Evan O'Dwyer, said the ruling would end much of the confusion surrounding the retrospective element of the drink driving penalties.
"It clarifies the confusion that existed to the extent that the law on the restoration of driving licences is a prospective law only."
He said the ruling could also act as a test case for those drivers disqualified for longer periods.
"Those people who were disqualified under the old law are now permitted to apply to the Courts to get their licences back under the old law. They don't come under the terms of the new law," he said.
It is difficult to estimate how many drivers were affected by the confusion.
Some 27,836 drink drivers appeared before the district courts in 2006 and, according to the Garda, over the five years to 2005, the average conviction rate was 39 per cent.
Mr O'Dwyer said large numbers of applications for the restoration of a driving licence had been adjourned pending clarification of the law: "A lot of people have had cases adjourned to have the law clarified. The decision should pave the way for all those people who have applications to restore driving licences lodged in court but adjourned."
Under the new penalties the minimum period of disqualification for drink driving increased from three months to one year, and fines for the offence were increased.
The new legislation also stipulates that only drivers disqualified for more than two years are allowed to apply to have their licence restored.
All those disqualified for a shorter period are required to serve their ban in full.
Up until then, drivers could apply to get their licence back once they had served half their disqualification.
In April this year, shortly after the new rules were signed into law, the then Minister for Transport Martin Cullen told the Dáil they were intended to have a retrospective effect, when he said they applied to offences "whether before or after the commencement of Section 7 and has a retrospective effect".
