Just being photographed with a tight smile either entering or leaving the inquiry carried with it a stain of guilt by association. Best to stay a mile away.

Politicians, in general, have little to fear from the Disclosures Tribunal, but one senses that old fears, however groundless, are resurrected as the cameras in the castle yard hove into view.

Yesterday, three high- profile political figures gave evidence.

Micheál Martin was there to answer questions about his walk-on role in the Maurice McCabe story. In 2014, following a meeting between the two men, the complaints of Garda malpractice that Sgt McCabe had been trying to highlight were finally addressed. The ultimate outcome was the O’Higgins commission, which in 2016 largely upheld the complaints.

Of more interest to the tribunal was a meeting the Fianna Fáil leader had with one of his TDs, John McGuinness, in February 2014. The TD thanked his leader for raising Sgt McCabe’s malpractice claims in the Dáil as Mr McGuinness was, by that stage, of the belief that the Cavan-based sergeant was somebody of substance.

Mr Martin confirmed that on that occasion, Mr McGuinness had told him of the meeting he had had the previous evening with the then Garda commissioner in a carpark, where Martin Callinan told him Sgt McCabe was a child abuser. This was entirely false, and the tribunal is examining whether such allegations were generated in an attempt to smear Sgt McCabe.

The meeting between Mr Martin and Mr McGuinness provides the latter with a near-contemporaneous account of the conversation with Mr Callinan, the substance of which the former commissioner denies.

In response to questioning, Mr Martin said he did not tell anybody else what Mr McGuinness had revealed. “When a person is accused of child abuse and it gets into the public domain, it’s very hard to put it back,” he said.

The second witness was former Labour Party leader and minister, Pat Rabbitte.

His time in the witness box was not as comfortable. He was asked about a statement he made on RTÉ’s Prime Time about something that had been said to him by a retired garda about Sgt McCabe after a radio programme in 2014.

What emerged at the tribunal was that the retired garda he had referenced was his driver when he served in cabinet. Mr Rabbitte admitted he had been reluctant to drag into the tribunal the driver, John Kennedy, with whom he had a close working relationship. But once the tribunal asked him to identify his source, he complied.

Mr Rabbitte said the driver warned him about Sgt McCabe after he had praised the Garda sergeant on the radio.

“He [Mr Kennedy] wanted to warn me in my own best interests about wading into a controversy when rumours on the grapevine suggested he [McCabe] might not be a man of the character I said he was,” Mr Rabbitte testified.

The driver said Sgt McCabe couldn’t be trusted and that “his own colleagues believed that he couldn’t be trusted with children”.

Mr Rabbitte also said that further verification could be sought from his private secretary at the time, whom he told about the remarks.

Mr Kennedy denies saying any such thing. In the afternoon he gave evidence that he had never said “this horrible thing I was alleged to have said about Sgt McCabe which has upset my family deeply”.

There is an obvious chasm between the two men’s recollection. Mr Kennedy is put out that Mr Rabbitte would say what he had said. At the outset of his evidence, the former driver described that he and the former minister “got on very well, but he could be grumpy. He didn’t talk much in the mornings.”

Mr Justice Peter Charleton made a point of informing Mr Kennedy that he accepts that if the exchange took place, it was not in the nature of “malicious gossip” but a “confidential discussion”.

The third political figure to give evidence was Housing Minister Eoghan Murphy. He was in and out in 15 minutes, having quickly raked over his time in the public accounts committee in 2014 where Sgt McCabe’s complaints of penalty points abuses were heard.

The last witness for the day was the former secretary general of the Department of Justice, Brian Purcell. He told the tribunal he had no knowledge of a smear campaign against Sgt McCabe. He certainly did have a close working relationship with the commissioner of the day, Mr Callinan.

The pair exchanged texts before and after Mr Callinan’s appearance at the PAC. “Well done exceptional performance under fire,” the sec gen wrote to the commissioner minutes after the PAC meeting concluded.

There were also texts a few weeks later when a protest was held outside Mullingar Garda Station in support of Sgt McCabe. The texts mention a few well-known figures who were present.

“You can judge a man by his friends,” wrote Mr Purcell.

“Some shower Brian,” replied Mr Callinan.

The closeness of the relationship between the respective office holders is a matter that will surely come under the microscope in the current attempts to reform how An Garda Síochána operates.