No misconduct action was taken against Greater Manchester police officers despite hundreds of complaints being lodged over one year, new figures show.
The Police Federation said the actions of a small proportion of officers from some forces should not harm the police's reputation.
However, the figures come in the wake of a number of high profile cases of police misconduct and criminal behaviour nationally.
These include former West Midlands detective Nicholas Taylor, who was found guilty of gross misconduct for selling sexual services to strangers, and Met officer Wayne Couzens, who was sentenced to life in prison for the kidnap, rape and murder of Sarah Everard last year.
Home Office figures show there were 251 formal complaints about officers in Greater Manchester Police in the year to April 2021.
But none were referred to the official disciplinary process, launched when an officer is deemed to have a case to answer for misconduct or gross misconduct.
Overall, no action was taken in response to any complaints.
A small number of allegations involving actions that do not amount to misconduct but fall short of expectations of police behaviour led to reflective review proceedings or performance reviews.
The complaints in 2020-21 involved 151 Greater Manchester police officers – an officer can be subject to more than one allegation and an allegation can involve multiple officers.
Across England and Wales, 14,393 official complaints were made against police officers.
Only 1% of these led to an official process to hear the case, while no action was taken in 92% of grievances raised.
The Police Federation of England and Wales said most officers "come into the police service to protect the public and act with integrity and respect".
Phill Matthews, conduct and performance lead at the Police Federation, condemned the behaviour of a small minority, which he said should not taint the police's reputation.
Mr Matthews said: "The police service is very good at uncovering those that don’t deserve to be in the job."
Greater Manchester figures also show there were 131 allegations of "conduct matter" offences, where there is an indication a crime has been committed – involving 115 police officers.
There were also 19 allegations against 14 officers for "recordable conduct" matters, including those that caused serious harm or death, and allegations of sexual offences and corruption.
No conduct matters or recordable conduct matters resulted in misconduct action.
The Independent Office for Police Conduct, which investigates the most serious police misconduct allegations, said an investigated case may not always lead to a finding of misconduct.
"There are a range of options including organisational or individual learning, providing an explanation, or providing an apology," a spokesperson added.
"These are all designed to have a range of options to resolve the complaint.
"Therefore, only the most serious cases will result in proceedings."