LONDON – The mayor of London ordered an investigation into racism at the Metropolitan Police on Monday, after black police complained about rampant discrimination.

Both the Black Police Association and the Society of Black Lawyers have urged minorities not to join the London force, saying they would not receive fair treatment in the competition for promotions.

Mayor Boris Johnson, who took control of City Hall in May, said he wanted the inquiry to determine whether recent changes to combat racism have taken hold in the force. If not, he said, investigators should offer recommendations.

“Policing a multicultural capital requires the police to have the full confidence of the communities they serve as well as its own staff,” Johnson said. The inquiry also will study how police deal with religious issues.

The Society of Black Lawyers has also asked the independent Equality and Human Rights Commission to investigate alleged racism within the force.

“There has been significant progress in the overall recruitment of minorities, but we are seriously concerned that many officers seem to have hit a glass ceiling,” said the society's chairman, Peter Herbert.

“They are not getting into specialist sections of the police,” he said, noting there were few minorities on the anti-terrorist squad or in special anti-crime units dealing with problems in the African and Caribbean communities.

“These concerns go to the heart of whether you can have a police force capable of crime reduction in a multiracial city,” Herbert said.

The police force has been grappling a number of problems in recent years.

Last week Johnson forced police chief Ian Blair to step down, following a string of missteps including the police shooting of a Brazilian commuter mistaken for a suicide bomber.

Assistant Commissioner Tarique Ghaffur also recently filed a lawsuit against the force for alleged religious and racial discrimination.