Three of Britain's largest police forces have been criticised for "poor" handling of discrimination complaints, and being far more sympathetic to those made by their own staff rather than the public.
The West Midlands, Greater Manchester and West Yorkshire forces were accused of "significant" failings in the way they dealt with allegations of racism and discrimination, by the Independent Police Complaints Commission (IPCC).
The three forces upheld between 11% and 13% of complaint allegations from the public but by contrast, more than half of the 32 investigations into discrimination allegations studied by the watchdog, which had been made by the police themselves were upheld, the watchdog found.
The IPCC said complaints brought by members of the public were "poorly handled from beginning to end".
Of 170 complaints from the public - out of 202 complaints in total examined by the IPCC alleging discrimination - 94 were investigated and, of those, no discrimination allegations were upheld, it said.
"We came across numerous examples that seemed to show that internally reported conduct is taken more seriously than complaints," the report said.
A lack of up-to-date training in diversity issues lay behind many of the complaints, the report said.
"The police in these force areas do not appear to have a good understanding of the diverse communities they serve," it said.
Dame Anne Owers, chair of the IPCC, said: "Our findings are stark - generally complaints of discrimination made by members of the public are poorly handled from beginning to end - in relation to the way the complaint is investigated, the conclusions drawn and, importantly, the contact with the complainant.
"It is vital that police forces deal effectively with allegations of discrimination.
"For particular sections of the community, likely to be more distrustful of the police, or more vulnerable, or both, they are a litmus test of confidence in policing as a whole and of the police's understanding of the communities they serve.
"While we welcome the fact that officers are prepared to report and challenge their colleagues when it comes to discriminatory behaviour, allegations made by members of the public need to be handled equally seriously and dealt with effectively."
The IPCC said 173, or 78%, of the allegations examined were about race.
Its remit looked into the way the three forces dealt with allegations in relation to any kind of discrimination including race, disability, age, gender and sexual orientation.
From the details that were recorded, most complainants were male, Asian, and aged between 26 and 35-years-old.
The report has been released after an IPCC investigation published last July into the Metropolitan Police's handling of race discrimination complaints revealed significant weaknesses in complaints handling in general as well as concerns about the way it investigated allegations of racism.
The IPCC said it chose to examine Greater Manchester, West Yorkshire and West Midlands police forces as the next three biggest forces after London, in an attempt to see whether there were similar concerns outside the capital.
West Yorkshire Police Deputy Chief Constable Dee Collins rejected the report's claim that the force did not have a good understanding of the communities it serves, saying: "We are very disappointed with the suggestion that we are 'failing at every stage'.
"Furthermore, we refute the report's assertion that we 'do not have a good understanding of the communities (we) serve'.
"West Yorkshire Police officers and staff have contact with thousands of people every day, often in distressing and difficult situations.
"The vast majority of those instances not only pass without complaint, but often result in positive comments and letters praising our people."
Detective Chief Superintendent Paul Rumney, from Greater Manchester Police, said: "There will now also be a review of how discrimination and other public complaints are handled.
"I am committed to ensuring the public has the confidence to make a complaint to us if they feel they have been treated inappropriately in the knowledge that their concerns will be thoroughly investigated to the highest standard, hence all allegations of discrimination will now be investigated."
He added: "We know there is a lot of work to be done but we are absolutely determined to make our system more accessible, timely and effective both for the public making complaints and the officers subject of them."