"The effect is still more marked in some parts of the capital. Police in the affluent area of Kensington and Chelsea charge black people caught in possession of cocaine seven times as frequently as white people. The differential for charging for cocaine possession was between five and six times for areas including Richmond, Harrow and Wandsworth."
http://www.theguardian.com/world/2013/aug/21/ethnic-minorities-likely-charged-drug-possession
"The effect is still more marked in some parts of the capital. Police in the affluent area of Kensington and Chelsea charge black people caught in possession of cocaine seven times as frequently as white people. The differential for charging for cocaine possession was between five and six times for areas including Richmond, Harrow and Wandsworth."