The High Court has dismissed Garda Keith Harrison's bid to have findings made by the Disclosures Tribunal against him quashed.

The Donegal-based garda, who was strongly criticised in the tribunal's interim reports, brought proceedings that centred on an alleged prior professional interaction between tribunal chair Mr Justice Peter Charleton and a witness, Chief Superintendent Terry McGinn.

The alleged prior engagement, which led to a claim of objective bias, related to when Chief Supt McGinn was the Garda liaison to the Morris Tribunal which considered allegations about gardaí in Donegal between 2002-2005 when Mr Justice Charleton was that tribunal's senior counsel.

In her judgment today, Ms Justice Aileen Donnelly said she was satisfied to dismiss the action on the basis that "no reasonable person could have a reasonable apprehension of bias based on the overlapping working period" when Mr Justice Charleton and the chief superintendent worked at the Morris Tribunal.

The judge noted that the claim being made was one of objective bias only and that there was no suggestion made by Garda Harrison's lawyers that Mr Justice Charleton was in any way biased in the findings he made in the interim reports.

Garda Harrison had sought an order quashing findings made in the Disclosures Tribunal's second interim report and the findings of the third interim report in so far as it relates to him.

Garda Harrison claimed the tribunal rejected allegations made by him and his partner, Marissa Simms, and had exonerated others they had made complaints about.

Their claims included that Ms Simms was compelled by gardaí to make a statement against Garda Harrison which led to a referral to the child and family agency Tusla.

Garda Harrison also alleged he was the victim of a five-year intimidation campaign after arresting a fellow officer for drink driving in 2009.

Garda Harrison and his partner, Marissa Simms

In an interim report, Mr Justice Charleton said all the allegations made by Garda Harrison - who was criticised by the tribunal - and Marisa Simms that the tribunal examined were "entirely without any validity."

Mr Justice Charleton praised the conduct of Chief Superintendent McGinn and her management of the Donegal Garda Division and was a key witness in relation to matters contained in protected disclosure made by Garda Harrison.

He brought the proceedings after becoming aware of newspaper reports which show a prior involvement between the judge and the chief superintendent.

The articles quoted criticism of a reconstruction from the Morris Tribunal, broadcast on RTÉ Radio, which created a poor impression of Chief Supt McGinn.

The articles quoted Mr Justice Charleton as saying that "all those who had worked with Chief Supt McGinn had great respect for the assistance she had given the Morris Tribunal and it was unfair to her that anyone might think she just was not interested in the truth."

It is claimed that the articles and transcripts of the Morris Tribunal showed that the judge did know the chief superintendent, had worked with her and was in contact with her.

Lawyers for the State in opposing Garda Harrison's action argued that the action should be dismissed and that the garda proceedings were fundamentally misconceived.

It also argued that no reasonable observer could form an apprehension of bias, as alleged by Garda Harrison, on the part of Mr Justice Charleton based on the professional interaction with Chief Supt McGinn at the Morris Tribunal.

In her judgment, Ms Justice Donnelly said that a comment made by Mr Justice Charleton many years ago when acting in a different tribunal about Chief Supt McGinn doing her best to assist that tribunal in finding the truth has been "elevated" by Garda Harrison "as a ground for claiming objective bias".

Based on the evidence before the court the judge said that Garda Harrison's claim "does not bear rational scrutiny".

Ms Justice Donnelly said the State's evidence was that Chief Supt McGinn's role as liaison was independent of the Morris Tribunal, her involvement with Morris was well known, and Mr Justice Charleton had no recollection of the comments he had made to the tribunal about the broadcast.

There was, the judge said, a minimal professional involvement between Mr Justice Charleton and Chief Supt McGinn. At the Morris Tribunal, they had worked in different offices on different floors of the building where the hearing took place.

"No reasonable person with knowledge of all the relevant facts could have a reasonable apprehension" that in regards to the matter investigated by the Disclosures Tribunal that Garda Harrison did not have a fair trial, Ms Justice Donnelly added.

Garda Harrison had also failed to demonstrate that the chief superintendent had acted improperly in any way.

The case will be mentioned again in October when all outstanding issues, including who will pay the cost of the action, will be considered.