Radical action is needed to tackle the "shocking" under-representation of black and minority ethnic (BME) people in police forces in England and Wales, a Commons committee has warned.
Ministers were urged to appoint a new diversity champion to hold the service to account over the issue.
No force in England and Wales has a BME representation which matches its local demographic, the Home Affairs committee said.
It cited figures showing that last year, 5.5% of officers were from a BME background, compared to 14% of the population.
Representation is "even lower" in the senior ranks, according to the committee's report.
Only two out of 201 chief officers self-identify as BME, while 11 forces have no BME officers above even the rank of chief inspector, according to previously published data.
Labour MP Keith Vaz, chairman of the committee, said: "The lack of black and minority ethnic representation in our police forces is stark and shocking, and no-one looking at this picture can believe it promotes effective policing.
"In order to police by consent in 21st-Century Britain, the police service must mirror the communities they represent, in religion, race and ethnicity."
He added: "If we compare the figures from 1999 and 2015, representation of the population in our police forces has progressed at a snail's pace.
"This was unacceptable in 1999 and it's totally unacceptable now. It is as if the Macpherson report was never written."
The Macpherson report on the Stephen Lawrence case, published in 1999, found evidence of "institutional racism" in Britain's largest force, the Metropolitan Police.
Mr Vaz added: "Despite good intentions from senior officers, diversity and representation in police forces has consistently failed to improve, we must take radical action now."
The committee called for the appointment of a new diversity champion with "the authority to hold all police forces to account for achieving proper community representation throughout the ranks ... by collecting and publishing data, promulgating best practice, and providing practical advice," the report said.
It also suggested steps including compulsory training on diversity issues for selection and promotion panel members, and introducing coaching and mentoring for BME officers.
Superintendent Manjit Thandi, of the College of Policing, said: "Police need to represent the communities they serve, and right now that is not happening enough.
"We are tackling this and have already delivered a bespoke evaluation and action plan to all 43 police forces to improve the recruitment, development, progression and retention of BME officers and staff."
Robin Wilkinson, of the Met Police, said the force "has done more than any force to improve representation from BME communities and we are pleased the committee has recognised that commitment".
He said nearly 30% of new recruits this year will be from BME backgrounds, adding: "On current projections, the MPS will reach 4,000 BME officers this summer.
"This is an increase of 75% over 10 years and an increase of 24% since 2012. BME officers are represented in the MPS at every rank up to and including Assistant Commissioner."
Home Secretary Theresa May - who attacked the lack of BME officers in the police service last year - said: "I have been clear that diversity is not an optional extra in policing.
"It goes right to the heart of this country's historic principle of policing by consent. For the public have trust and confidence in the police, and the police must reflect the communities they serve.
"That is why, since 2010, the Government has consistently challenged the police to improve diversity and tackle under-representation."
She added: "The police have made real improvements in diversity but the Government has been clear that there is more for forces to do. It is for local police leaders, led by the College of Policing, to rise to the challenge of reform."
National Police Chief's Council workforce lead Chief Constable Giles York said: "We take the findings of this report very seriously. A diverse workforce is essential for good policing and, in recent years, progress has been too slow despite the efforts of many forces and each having a plan developed with the College of Policing.
"Bringing in new people has been a challenge because of budget reductions. However, some areas are now beginning to recruit and, as this opens up, I am confident the mix will change."