Representation of the black and ethnic minority (BME) community in English and Welsh police forces has progressed at a "snail's pace" over the course of 16 years. In 2015, only 5.5% of officers were from a BME background compared to 14% of the general population, according to a police diversity report from the House of Commons Home Affairs Committee, published on 21 May.
In 1999, just 2% of officers in England and Wales' police forces were from BME communities, in contrast to 6.5% of the wider population.
The problem is even more severe at senior ranks with only two out of 201 chief officers self-identifying as BME. Eleven forces have no BME officers above the rank of chief inspector, previously published data had found.
Committee chair Keith Vaz called the findings "stark and shocking", saying: "No-one looking at this picture can believe it promotes effective policing."
The Labour MP added: "In order to police by consent in 21st century Britain, the police service must mirror the communities they represent, in religion, race and ethnicity.
"If we compare the figures from 1999 and 2015, representation of the population in our police forces has progressed at a snail's pace," said Vaz. "This was unacceptable in 1999 and it's totally unacceptable now. It is as if the Macpherson Report was never written.
"Despite good intentions from senior officers, diversity and representation in police forces has consistently failed to improve, we must take radical action now."
The latest findings prompted the committee to call on Home Secretary Theresa May to appoint a national "diversity champion" who will have "the authority to hold all police forces to account for achieving proper community representation throughout the ranks".
May said that "diversity is not an optional extra in policing". She added: "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."
Robin Wilkinson, of the Metropolitan Police said the force "has done more" than any other to improve BME representation. He added that almost 30% of newcomers this year will be from BME communities.
"On current projections, the MPS [Metropolitan Police Service] will reach 4,000 BME officers this summer," he said. "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."