Black people are more likely to face criminal charges for cannabis possession than white people, according to research by London's Metropolitan Police
The same group are also more likely to be stopped and accused of possession in the first place, the study has shown.
According to the recent monitoring, carried out by Scotland Yard to look at how possession of cannabis offences have been enforced, a total of 24,916 people were accused between January and April 2006.
Of those, the three largest ethnic groups to face accusations were African and Caribbean, with 9,925 people (40 per cent), followed by White Europeans, 9,477 people (38 per cent) and then Indian and Pakistani, 3,260 people, (13 per cent).
Further analysis showed people from an African or Caribbean background were the most likely to go on to be arrested and charged over cannabis possession.
Of those accused of the offence, 18.5 per cent or 1,844 people were later charged, compared to 14 per cent or 1,331 white Europeans.
However, 19.3 per cent of white Europeans (1,837 people) were given a caution, compared to 14.2 per cent of people from African or Caribbean communities (1,411 people).
A Scotland Yard spokeswoman said further work was needed to understand why more African and Caribbean people were charged than anyone else.
She said: "The decision to arrest and charge will vary on a case by case basis and is often dependent on a complex variety of factors."
These factors can include the amount of cannabis involved, previous offending history, whether admissions were made in interview, no comment interviews, which prevent the consideration of a caution, or circumstances where the discovery of cannabis is made after an arrest for another offence.
Drugs charges show 'black bias'