A senior garda informally warned the former head of the Road Safety Authority, Noel Brett, about using his phone to discuss allegations of garda penalty points abuse, RTÉ's This Week has learned.
The incident occurred while Mr Brett was in regular contact with sources close to Garda Sergeant Maurice McCabe in mid-2013 as RSA chief executive, and shortly before he left the roads safety body later that year to head up the Irish Banking and Payments Federation.
Mr Brett was the first high-ranking public official to call on the Garda Ombudsman to look into the allegations of widespread abuse of the system, which re-ignited the penalty points issue in June 2013.
Mr Brett's intervention led to the then minister for transport, Leo Varadkar, backing the RSA chief's call for a further GSOC review.
A series of reports have since backed up Sgt McCabe's allegations about the inappropriate cancellation of penalty points by some gardaí.
The senior garda who contacted Mr Brett about the speaking on his phone at that time did so unsolicited and in what is believed to have been an attempt to warn him about the risks, and how intensely senior garda management was dealing with the leaking of certain information into the public domain.
While it is believed that Mr Brett did not ask GSOC to examine whether his or anyone else's phone calls were being intercepted, it is understood that Mr Brett subsequently discussed the issue of whether his phone calls may have been listened in to with another senior garda.
The second senior garda officer to whom Mr Brett spoke held a high-ranking role in garda headquarters and has worked closely with successive garda commissioners.
RTÉ's This Week understands that this second senior garda told Mr Brett that it was "likely" gardaí had intercepted or listened in to conversations involving the RSA chief, a well-placed security source said.
However, neither of the two senior gardaí to whom Mr Brett spoke had direct evidence of any surveillance relating to his phone or of conversations involving Mr Brett and Sergeant McCabe or others.
The revelation indicates how some senior gardaí believed that attempts to control the leaking of information in relation to penalty points, and possibly other garda scandals, had reached such an intense level by mid-2013 that this may have included the interception of phone conversations involving not just garda whistleblowers but also a small number of senior public officials.
Mr Brett is now the chief executive of the Irish Banking and Payments Federation and is also on the board of the Policing Authority.
He issued a brief one-sentence statement to RTÉ when contacted this weekend.
He said: "Whilst it may have been informally suggested that I needed to be careful in my interactions with whistleblowers when I was working as CEO of the RSA, I am totally satisfied that my telephone was not intercepted and I did not deem it necessary to change my phone number, phone provider or telephone usage behaviour."
A spokesman for the garda press office said they were not in a position to respond as they received the query over the weekend when many key staff were not available, but would do so in due course.
