Alan Shatter (Dublin South, Fine Gael) | Oireachtas source

The cancellation policy also seeks to reflect the guidelines of the Director of Public Prosecutions for prosecutors and the Garda declaration of professional values and ethical standards, both of which govern other factors that adhere to the principles of fairness and proportionality and provide that in pursuing their public duties, gardaí are required to adhere to the principles of legality and apply the law in a manner that is fair, equitable and appropriate to the particular circumstances of individual cases. In essence, termination or cancellation occurs where it is believed the evidence would not sustain a prosecution or a prosecution would not be appropriate, fair or proportionate. Gardaí at the rank of superintendent, district officer or inspector acting district officer have the discretion to authorise cancellation in appropriate circumstances. I illustrated some of these circumstances during Question Time. There are exemptions relating to emergency vehicles or in cases where a medical necessity has resulted in an individual speeding. I want to absolutely confirm that these allegations will be fully and properly investigated. The result of the investigation will be made known. There is no question of a conspiracy or cover-up, regardless of how much the Deputies want to advocate that there is.

See this speech in context