Most complaints are informally resolved, conciliated, sent for preliminary enquiries or investigated. However, the Authority may decide [Police (Complaints and Disciplinary Proceedings) Act 1985 s.21] that a complaint should not be investigated or further investigated if:

A complaint is not investigated if a person has been charged with an offence and the subject of the complaint is bound up with the proceedings before the court. In these circumstances, rather than encroach on the court's jurisdiction, the Authority waits for the court's decision before deciding whether to investigate the complaint. Delaying the investigation until the court proceedings have ended avoids having the prosecution and defence cases compromised or prejudiced and, if a court has ruled on the relevant subject matter, may save time and cost of an investigation.

As long as the Authority agrees, the police may try to conciliate a complaint if there is some chance that it can be resolved to the satisfaction of all concerned. This applies to all types of complaints [Police (Complaints and Disciplinary Proceedings) Act 1985 s.22].

To resolve less serious allegations (for example, use of bad language, shoving and jostling in a crowded situation) a person making a complaint can nominate whether or not to try to informally resolve the complaint. This process of informal resolution is normally completed within 14 days. The person making the complaint can withdraw consent at any time during the process and the complaint may then be dealt with on a formal basis. If a complaint can be informally resolved or conciliated, the costs and delay of an investigation are avoided.