The IPCC is not fit for purpose
This video clip exposes that there is one death in police custody every week. A few years ago there was a death in Bournemouth Police Station. The inquiry was supervised by the IPCC as are most complaints against the police. The police are quite happy with this as the IPCC has no power to actually prosecute any police officers.
All they can do is oversee a supposed investigation carried out by the police force that are being complained about. It is like asking Ronald Cray to investigate Reggie. All the IPCC can do is refer police misconduct or negligent shootings ect to the CPS.
Unfortunately this leaves the local CPS to prosecute officers from the same local police force. Unfortunately due to the criminal justice boards that the government has set up for each county police force, this only exasperates the situation.
In the case of Dorset, you have senior police officers who have a vested interest in covering up the misconduct of their officers, urinating in the same pot as senior CPS prosecutors and others in the county, all having tea and sandwiches together paid for by the government at criminal justice board meetings.