Controversial police stop and searcher powers are to be overhauled, Home Secretary Theresa May has said.

She told MPs that up to 27% of police searches under the powers may have been illegal, with innocent people searched without reasonable grounds. She also threatened to change the law if the number of searches did not come down.

Her comments come in the wake of a consultation about the powers, which highlighted issues that the minorities were unfairly targeted for searches by police, with black people six times more likely to be stopped than white people.

She said that recent changes in London policing show that it is possible to reduce the use of such tactics and still reduce crime, saying:

Since February 2012, the Metropolitan Police have reduced their overall use of stop and search by 20%. They have reduced no-suspicion stop and search by 90%. In the same period, stabbings have fallen by a third and shootings by forty per cent. Complaints against the police have gone down and the arrest ratio has improved.

The Metropolitan Police have welcomed the changes, with Commander Adrian Hanstock commenting:

“We have made significant improvements over the last two years to not only reduce the total number of people we search, but also to ensure that our officers focus on those areas and types of crime that the public are most concerned about and this work has been acknowledged by the Home Secretary.”