As CP says, it varies from force to force. My only experience is with Surrey and Thames Valley. If the evidence is good enough, Surrey will tell you that they are pursuing it, giving a list of options they will take from a letter up to prosecution. Presumably that is basically telling you that they are issuing an NIP. My one and only submission to Thames Valley was less informative. Having submitted the video, description, etc., their stock message seems to say they can pursue it only if they have corroborating evidence from an independent source. That makes no sense as I was the independent source (was only a witness and had no part in the offender in front jumping the red light), and there is unlikely to be any other evidence. Silence follows. Makes me less inclined to go through the effort if I see something in TVP's patch again.