The Fennelly Commission Report has stated that one of the most surprising findings is the "almost total ignorance at the highest levels of the force" that the main telephone line at garda divisional stations outside of Dublin was being recorded since 1995/96.
The commission was established in March 2014 to examine the circumstances surrounding the retirement of then garda commissioner Martin Callinan, and the taping of phone calls at garda stations.
It states that knowledge of the recordings of certain non-999 lines remained confined to members of the Telecommunications Section and an unknown proportion of local garda officers.
The report states that the systems installed and operated at garda stations to record and retain non-999 calls were unlawful.
An Garda Síochána had no common law authority to install and operate the systems, the report states.
By doing so it infringed the rights of personal privacy of those recorded and it follows that gardaí were not legally authorised to use the recorded information from non-emergency calls.
The commission said there was no evidence of widespread abuse but said this could not be ruled out.
It also found gardaí had no intention, or did not deliberately, attempt to record calls between solicitors and clients.
The report examined phone recordings in Bandon Garda Station where the investigation into the murder of Sophie Toscan du Plantier was based.
It said it was concerned that the calls show gardaí were prepared "to contemplate" altering, modifying or suppressing evidence, although there was no evidence this was actually carried out.
The fact that senior ranks of the force were almost totally unaware of the existence of recording systems meant that no minister for justice had any knowledge of the existence of garda telephone recordings from 1980 to 2006.
There is no evidence the Attorney General knew about the recordings prior to being informed by the Garda Commissioner in November 2013 and there is no evidence the Director of Public Prosecutions knew of recordings prior to 2014.
The commission said that in 1996, the Chief Superintendent of IT and Telecommunications approved the recording of the main station number at divisional stations, without understanding that this is what he was doing.
By doing so he crucially inhibited the transmission of knowledge of non-999 recording to the upper ranks of An Garda Síochána.
Garda commissioners knew to 'some extent' of 999 recordings
The commission found that as well as current Garda Commissioner Nóirín O'Sullivan, five former garda commissioners all knew to "some extent" that 999 calls or emergency calls were recorded.
However, it found none of them were aware of the "systematic recording" of non-999 calls.
It found that in particular, none knew that the main station telephone number at divisional stations outside Dublin had been recorded as a matter of routine since 1995.
The commission cited a case in July 2011 when evidence was given in Waterford Circuit Court during the trial of four members of the force.
It said this ought to have alerted the senior ranks of the force to the fact of non-999 telephone recording, although it "would have been late in the day".
Force lacked clear policy on telephone recording
It said the force lacked any clear policy regarding telephone recording at garda stations.
It also said at no stage since since the first recording system was installed at Dublin Castle in the 1970s did An Garda Síochána as an organisation or any garda commissioner adopt or circulate a formal policy on the operation of telephone recording systems.
The consequence of this is the organisation never, at any time, gave any consideration to the lawfulness of recording telephone calls either from the general public or between members of the force.
The report states that some technicians and other officers did raise questions and concerns from time to time over the operation of the telephone recording systems, in the expectation that those concerns would be put to senior management.
"But it seems that these concerns were either not understood, not put before senior management or simply not responded to."
Alarm bells in Government Buildings
The commission said alarm bells sounded in Government Buildings in March 2014, when it was reported that An Garda Síochána had, for many years, been recording non-999 telephone calls at garda stations.
It said the Taoiseach, on the evening of 24 March, having been briefed by the Attorney General, caused the
gravity of the matter to be conveyed to the Mr Callinan, who concluded that he was expected to consider his position as garda commissioner.
He did so and announced his retirement.
The commission found the former commissioner had, several months previously, on his own initiative, caused the recording to stop immediately on learning of its existence.
He had also formally reported the matter in writing to the Department of Justice on 10 March.
"Through mishap" the commission said this fact was unknown to the Taoiseach, the Attorney General or the Minister for Justice until after the events of 24 March.
It found if it had been, the events which precipitated Mr Callinan's retirement would not have taken place.
No deliberate abuse of power found
The report concludes that "in spite of poor communication and even blunders and of the underlying lack of lawful authority, this is not a history of anything approaching deliberate abuse of power".
The senior ranks of An Garda Síochána were unaware of the recording.
The technicians acted, on the whole, responsibly and conscientiously.
There was no garda system of snooping, spying or intrusion into private life and certainly not of listening to solicitor/client calls, it found.
However, it states that An Garda Síochána is unlawfully in possession of a very large volume of recorded material, most of it entirely innocuous.
The commission says this includes an unknown and unknowable quantity of sometimes sensitive information about the private lives of individuals, including members of An Garda Síochána.
Report 'reinforces determination' for root and branch review
The Government said the report reinforces its "determination to undertake a 'root and branch' review of An Garda Síochána."
In a statement following the publication, the Government says the report "makes many findings of great concern" to it including in relation to the unlawful nature of the recordings, lack of effective oversight and procedures, and in relation to the content of certain telephone recordings relating to the investigation of the death of Sophie Toscan du Plantier.
The statement goes on to say that the Government will take account of the Commission's findings when finalising its proposals for a review of the force.
It goes on to say that Tánaiste and Minister of Justice Frances Fitzgerald will also consider, in conjunction with the Policing Authority, what short-term measures may be required in terms of legislation, technology or practices and procedures in response to the findings and recommendations of the Report.
The Fennelly Commission report was due to be completed by the end of 2014 but was finally published today.
An Garda Síochána to examine report
In a statement this evening, An Garda Síochána said it "welcomes Judge Fennelly's finding that 'no widespread or systematic, indeed probably no significant, mis-use of information derived from non-999 telephone recording has taken place'."
In a statement, it said: "An Garda Síochána welcomes the judge's clarity on the legal status relating to the retention of phone data. We will work with the relevant authorities on the recommended legislation on this matter.
"There will now be a detailed examination of the report and where any organisational issues are identified they will be addressed as quickly as possible."