Parts of Britain are operating their own forms of justice as some minority communities take the law into their own hands, the Chief Inspector of Constabulary has claimed.
Tom Winsor said that some ethnic communities are turning their backs on police and rarely, if ever, call them to deal with crimes as serious as murder and sexual assaults against children, instead dealing with them in their own way.
In an interview with The Times Mr Winsor praised the enrichment multiculturalism brings to the UK, but said that "when it comes to criminal justice we have one system and everyone, wherever they come from, is equal under the law and entitled to fair treatment by law enforcement agencies."
He told the newspaper that police were never called to some neighbourhoods as they "administer their own form of justice", saying that this was not carried out by criminal gangs but by "law-abiding people".
Mr Winsor said: "There are some communities born under other skies who will not involve police at all. I am reluctant to name the communities in question but there are communities from other cultures who would prefer to police themselves.
"There are cities in the Midlands where the police never go because they are never called. They never hear of any trouble because the community deals with that on its own... They just have their own form of community justice."
Mr Winsor said some chief constables receive "close to zero" calls from some areas, and that police are not afraid to go to such areas, but that they do not know what is going on as communities do not tell them.
He said: "They don't know what injustices are being perpetrated... It's almost a closed book because we can't go there so don't know. It could be anything from low-level crime right up to murder... (Honour killings) are the most extreme example. That is murder. There is no honour in it."
Mr Winsor compared the situation in some parts of the UK to Northern Ireland during the Troubles, but said the difference now was that it was law-abiding citizens operating their only system of law, rather than criminal gangs.
He told the newspaper increased diversity in the police across all ranks could help tackle the situation, though he did not think there was "institutional racism" in the Metropolitan Police.
But some police bosses did not recognise the problem.
Chris Sims, chief constable of West Midlands Police, told The Times that areas with a high density of minority communities accounted for high volumes of calls to his force.
Chief Constable Simon Cole, Association of Chief Police Officers National Policing Lead on Local Policing, said: "The relationship between the public and the police is critical to our policing model and builds safe, cohesive neighbourhoods.
"For this reason, police work hard to build relationships with all members of our communities. Every area in England and Wales has a neighbourhood policing team that is out in the community, talking to people, understanding their priorities and acting to address their problems.
"Making the service more representative of the people that we serve is important; forces have encouraged more black, Asian and ethnic minority people to join the police as officers, members of the Special Constabulary or as volunteers. We've also involved community representatives in advisory groups and panels so their voices are heard.
"Citizens being engaged and contributing to making where they live a better place is a positive thing that we wouldn't want to change; working with the police to do that helps to make local people safer."
Meanwhile, Mr Sims said there was "no evidence" of crimes being under-reported in minority communities in the West Midlands force area.
The force polices a region which includes a host of diverse ethnic minority communities in its towns and cities, including Birmingham and Wolverhampton.
The chief constable said his officers had worked hard building strong links, pointing to the trust and co-operation shown between police and the region's Muslims when that community found themselves targeted by a spate of mosque bombings carried out by Ukrainian engineering graduate Pavlo Lapshyn last year.
Mr Sims added: "The experience of West Midlands Police's officers and staff who actively work day in day out with our communities could not be more different than suggested by Mr Winsor, assuming he's referring to West Midlands
"There is no evidence to suggest that the under reporting of crimes is a significant issue here in the West Midlands and that some communities therefore feel compelled to take the law into their own hands.
"However we're not complacent and we know there's always more we can do to build trust and confidence.
"In fact, I would very much welcome the opportunity to see any evidence which supports Mr Winsor's bold claims.
He said: "As a force we enjoy excellent relationships with the diverse communities we serve and positively encourage members of the public to report crimes to us.
"Major events such as the terrorist attacks on mosques across the Black Country last year saw key community representatives stand shoulder to shoulder with the police throughout the investigation and beyond.
"This is a typical example of our strong links with the community."
Mr Sims said a rise in the reporting of hate crimes over the last year was a direct result of what he called "increased trust in police within communities and their confidence in our ability to thoroughly investigate offences and bring offenders to justice."
He added: "In addition, West Midlands Police recently launched a long-running campaign strengthening the force's commitment to protecting vulnerable victims, focusing on five key crime types including child sexual exploitation, forced marriage and female genital mutilation.
"This has already resulted in many more crimes being reported to us.
"These are just some of the issues communities tell us affect them and matter most."
Home Affairs Select Committee chairman and Leicester MP Keith Vaz said: "I am concerned by these claims. I have represented an inner city Midlands constituency, which is home to many diverse communities, for 26 years and have not seen any evidence to support the idea of a sub culture of secondary justice.
"The evidence in fact points the other way. Ethnic minority communities have developed impressive partnerships with the police and seek to report crimes and bring criminals to justice.
"It is hazardous to suggest that some communities have lost faith with the justice system of this country without providing specific evidence.
"I hope that Mr Winsor will back up his statements in his report. The Home Affairs Select Committee will also ask Bob Jones, the Police and Crime Commissioner for the West Midlands, about this matter when he gives evidence to us on Tuesday."