An offence has clearly been committed by the driver and whether is reported by an overzealous vigilante, a responsible citizen or a Police officer, prosecution must follow. There is nothing to think about - the camera clip is clear. Its no brainer and I doubt even 5 minutes was spent making the decision.
CPS cannot act as the judge and have to proceed with prosecution, unless there is a grey area. In this case bellend or no bellend who lodged the complaint, their hands are tied.
