“It would be a question of the utmost public concern if an undercover officer were effectively permitted to operate without justification, authorisation or oversight in Ireland.”
Gardaí in North West Mayo routinely harass people in the area with video cameras (as well as violence), however they don't like it so much when the camera is turned on them.
One point to note is how often the Gardaí switch their numbers. The Garda whose on camera at 2:57 is a particularly violent Garda. In this video his Garda number is GA454. Five days after this video was taken he was wearing MY218 and assaulted 3 peaceful protesters.