Researchers are calling for change after they found black people in England and Wales are almost nine times more likely than white people to be stopped and searched for drugs.
They said the situation had "got worse not better" four years after Theresa May – then home secretary – declared stop and search was "unfair, especially to young black men".
The joint study by the London School of Economics and Political Science, the Stopwatch coalition and drug law experts Release showed that although police use of stop and search had fallen significantly, there had been a rise in racial disparities in the policing and prosecution of drug offences.
Black people were stopped and searched at 8.7 times the amount of white people for drugs by 2016/17, according to the report. For other offences, it was 7.9 times the rate of white people.
Officers carried out 303,845 stops and searches in the year to March 2017, which is the lowest number since records started in 2001/02.
The practice has been condemned by critics who say it unfairly targets people from black and minority ethnic backgrounds.
In 2014, Mrs May introduced reforms to ensure powers were used in a more targeted way but Tottenham MP David Lammy said the new figures represented a "profound racial injustice".
Recounting the first time he was "frisked, groped and harassed" by police as a 12-year-old, he told The Observer: "Grounded in the fictitious narrative that drug use is especially prevalent among black and minority ethnic groups, the current practice of stop and search entertains a racist fantasy.
"As we speak, there will be young, white middle-class men smoking a joint at a campus university or having cocaine delivered to their dinner parties, but the police will be nowhere in sight."
According to the report, entitled The Colour of Injustice: Race, Drugs and Law Enforcement in England and Wales, drug searches made up 60% of all stop and searches – the majority for possession.
Black people are treated more harshly when they are found in possession of drugs, the researchers also found.
The analysis found the detection rate from stop and search is similar for all ethnic groups but black people were arrested at a higher rate than white people and handed out of court disposals at a lower rate.
For white people, arrests for drugs as a result of a search fell by 52% between 2010/11 and 2016/17 while the figure for black people did not fall at all, the report said.
Co-author of the study Dr Rebekah Delsol said: "More than four years after the home secretary declared that stop and search is unfair to young black men, it is shocking that the situation has got worse not better.
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"The police are clearly unable or unwilling to deal with the problem and a solution needs to come from elsewhere."
She added: "Forces that cannot use stop and search fairly and effectively should have the powers taken away."