The Home Secretary has been asked to intervene in a fresh police race row as it was claimed at least 20 forces blocked an inquiry into discrimination against Muslim officers.
Barely half of the 43 forces in England and Wales co-operated in an audit into the treatment of officers from ethnic minorities, the National Association of Muslim Police said.
In a letter to Jacqui Smith, Zaheer Ahmad, president of the association, also claimed information from the forces that did respond suggested routine racial harassment.
Referring to 10 years since the inquiry into the murder of Stephen Lawrence found the Metropolitan Police to be "institutionally racist", an association spokesman said its audit revealed: "We still do not have the level of diversity that the public rightly expects."
Progress on diversity was "painfully slow", he added.
The revelations come just days after it emerged Tarique Ghaffur, Britain's most senior Muslim officer, was considering suing the Metropolitan police for discrimination.
From the data provided to the association, it was revealed 95% of black and minority ethic officers are in the most junior rank.
Figures also revealed Muslim officers are almost "entirely absent" from specialist operations such as counter-terrorism - a move Mr Ahmad believed is hampering the fight against terrorism.
In the questionnaire, the association asked forces about the promotional prospects, rank and number of Muslim and black officers employed. Initially just 11 of the 43 forces replied - 23 co-operated when the deadline was extended.
From the replies it received, just 0.3% of police officers were found to be Muslim, compared with 3% of the British population.
