There were calls last night for major reforms to the State's witness protection programme after the Court of Criminal Appeal expressed concerns about it in its ruling denying an appeal by the drug-dealer John Gilligan.
Labour said the criticisms of the court were so strong that convictions secured using protected witnesses might fall in the future unless the scheme's flaws were addressed.
In a lengthy judgment yesterday, the Court of Criminal Appeal said there were "very disturbing factors in the way in which the authorities sought to obtain evidence" of key witnesses who gave evidence against Gilligan under the witness protection programme.
It added: "One of the most worrying features is that there never seems to have actually been a programme." Instead the system remained "fluid", with no clear guidelines, and witnesses increased their demands under it when their time to give evidence arrived.
Labour's spokesman on justice, Mr Joe Costello TD, said the programme should be put on a statutory basis. "This is not the first occasion on which the most senior judges in the country have been extremely critical of the programme, but the Government has taken no action to deal with these criticisms.
"A witness protection programme is an important part of society's armoury in the battle against organised crime. Similar programmes are operating in most developed countries, but they must operate on the basis of specific ground rules to protect against potential miscarriages of justice," Mr Costello said.
The programme was badly thought out and lacked clear guidelines regarding inducements offered to witnesses in exchange for their co-operation, he added.
Following a spate of gangland killings and the fresh outbreak of violence in the ongoing Limerick feud, the Minister for Justice, Mr McDowell, last month announced a review of the programme.
It is understood he is keen to expand it with a view to securing more gangland convictions.
The Minister is currently on holiday and was unavailable for comment last night. A spokeswoman said the Department had no comment to make on the Court of Criminal Appeal's judgment.
John Gilligan was sentenced to 28 years in prison two years ago by the Special Criminal Court. He was convicted of 11 drug-related offences involving the importation and sale of cannabis resin between July 1994 and October 1996. He was appealing on 20 grounds.
During his original trial the court heard evidence from three of Gilligan's former associates, Charles Bowden, Russell Warren and John Dunne. All three were taken into the witness protection programme.
They were offered a combination of incentives to co-operate including assistance to relocate abroad under new identities and the return of substantial amounts of money seized by gardaí which were understood to have been the proceeds of crime.
The Court of Criminal Appeal noted in its judgment yesterday that while the men were never granted official immunity for any crimes, charges were not pursued on some matters, even though a significant amount of evidence existed.