Transcripts of the O’Higgins Commission supplied to the Garda Síochána Ombudsman Commission for its investigation into the Mullingar meeting incident were missing crucial pages, RTÉ's Prime Time programme has revealed.

GSOC had to obtain a court order to get access to the transcripts from the Department of Justice because the transcripts are confidential under the provisions of the Commissions of Investigation Act.

GSOC obtained that court order in January and the transcripts were delivered on 20 February. However, GSOC confirmed in a statement yesterday that the transcripts that were delivered were incomplete.

The GSOC inquiry centred on an incident that occurred in the opening days of the O’Higgins Commission.

Counsel for the Garda Commissioner told the inquiry that he had been instructed to challenge Maurice McCabe's credibility and motivation.

He said that a senior garda would give evidence that Sgt McCabe had admitted at a meeting in Mullingar in 2008 that he only made his allegations of garda malpractice because he had a grievance against a senior officer.

However, Sgt McCabe had a tape recording of that meeting that proved this was not the case.

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Prime Time revealed that key pages in which Mr Justice O’Higgins confirmed to the inquiry that he had reviewed the tape of the Mullingar meeting and the remarks attributed to Sgt McCabe were not on it.

The hour that was missing was the hour in which the strategy outlined by the Garda Commissioner’s legal team collapsed.

That hour was also missing from the transcript supplied to the McCabe legal team during the commission hearings.

There was no mention of this incident in the O’Higgins Commission report.

A spokesperson for the Department of Justice said: "The particular pages identified by GSOC were not among the records of the Commission deposited with the Department in the first place."

The Department said there was "no question of transcripts being withheld from GSOC or of the necessity for an investigation. To the extent that some pages were not among the records deposited with the Department of Justice and Equality, the transcripts were not complete."

When the department realised they were missing they had to go back to the stenographer to source them.

Prime Time has established that there was no issue with the stenographer. That hour had been transcribed and submitted as normal during the course of the commission.