Police stop-and-search powers are often blamed for causing racial tensions in communities, but now the true scale of the problem has been laid bare.
In London, one police officer used stop-and-search powers 54 times in just six months, almost entirely on black men aged between 10 and 19, but didn't find enough evidence to make a single arrest.
A second officer with the Metropolitan Police used the same powers 33 times, with 29 stops targeting young black men, but again none of the searches lead to an arrest.
Nine officers with the London force were responsible for 312 searches between them, but again failed to arrest anyone, figures released under Freedom of Information laws to Channel 4 show.
Of those 312 searches, almost half were on young black men, while another 44 per cent were on black or ethnic minority Londoners.
The figures seem to suggest that a small but persistent number of officers are using stop-and-search legislation to disproportionately target ethnic minorities.
Nationally black and ethnic minority members of the public are up to six times more likely to be searched than white people.
The data was revealed after Home Secretary Theresa May launched an overhaul of the controversial powers this week.
Across the UK 35 police forces have opted in to the voluntary code of conduct with immediate effect, with the remaining eight phasing it in over the coming months.
The new system means that officers must have a specific reason for searching an individual, whereas under the previous system police only needed 'reasonable suspicion' that a crime had taken place
Forces will also have to record the outcomes of all stop and searches, and reveal whether the ground for the arrest and the reason for the search are linked.
The aim is to drive down the use of stop-and-search powers, which are seen by detractors are largely ineffective.
Dianne Abbot, Labour MP for Hackney, told Channel 4 News: 'There is not a black family in London who cannot tell you of these stories happening to them or someone they know.
'I give credit to Theresa May for being the first minister in 20 years to tackle the problem of stop and search powers.'
Stop and search has long been accused of causing racial tensions in communities, especially in London where they were one of the main catalysts for the 1981 Brixton race riots.
As part of Operation Swamp 81, around 1,000 people were stopped and searched in Brixton in just five days, with just 82 arrests made.