Rules governing the use of controversial stop and search powers are to be relaxed by ministers in an effort to tackle rising violent knife crime.
Thousands more police officers can now authorise enhanced searches after ministers altered stipulations as part of efforts to tackle the use of blades.
From Sunday, forces in badly-affected areas will be able to activate powers designed to head off violence at a lower level of seniority.
Home Secretary Sajid Javid has also made it simpler for police to use Section 60 of the Criminal Justice and Public Order Act 1994.
This allows officers to stop and search anyone in a designated area for a limited time if serious violence is anticipated.
Once authorised, police can stop and search people or vehicles regardless of whether they have reasonable grounds for suspecting they will find offensive weapons or dangerous items.
Javid has now lifted two conditions introduced in stop and search guidance rolled out in 2014 when Theresa May was home secretary.
Rules under a nationwide “best use” scheme, which all forces are signed up to, require a section 60 order to be signed off above chief superintendent rank, and states the authorising officer must reasonably believe serious violence “will” take place.
Under the changes announced this weekend, which initially apply to seven forces, the rank at which section 60 can be approved has been lowered to inspector.
This will result in at least 3,000 more officers being able to authorise the use of the powers, officials estimate.
In addition, the degree of certainty required has been lowered, so that the authorising officer must reasonably believe serious violence “may” occur.
Javid said: “Stop and search is a hugely effective power when it comes to disrupting crime, taking weapons of our streets and keeping us safe.
“That’s why we are making it simpler for police in areas particularly affected by serious violence to use Section 60 and increasing the number of officers who can authorise the power.”
May, who will host a summit on serious youth violence on Monday, said stop and search is an “important tool” in the fight against knife crime.
She added: “As a whole society, we also need to take a hard look at the root causes of these crimes so we can intervene earlier and stop young people from being drawn into violence in the first place.”
Section 60 is often enforced after an incident of serious violence when police anticipate reprisals, or at major public events.
The power was deployed at last year’s Notting Hill Carnival, and during an operation outside Stratford station in east London last year.
In 2017/18, police in England and Wales carried out 2,501 stops and searches under section 60, up from 631 in the previous year.
Overall, police stop and search activity plunged in recent years.
As home secretary, May introduced reforms to ensure more targeted use of the powers following criticism they unfairly focused on black and minority ethnic individuals.
Javid has backed the tactics since his appointment last year.
He has already announced plans to widen the circumstances in which they can be deployed to combat acid attacks and misuse of drones.
Metropolitan Police Commissioner Cressida Dick said her force has increased its use of Section 60 in the last 18 months.
She said: “Stop and search is an extremely important power for the police.
“Our well-trained officers, acting on intelligence, use their powers professionally every day to remove weapons and other illegal items from the streets and to arrest violent offenders and those who habitually carry weapons.”
The announcement forms part of the government’s efforts to tackle surging violence after a spate of fatal stabbings prompted warnings of a “national emergency”.
There were 285 homicides where the method of killing was by a knife or sharp instrument in the year to March 2018 - the highest number since records started in 1946.
The Section 60 changes will initially apply in London, West Midlands, Merseyside, South Yorkshire, West Yorkshire, South Wales and Greater Manchester for up to a year.
Forces are expected to engage with communities on its use, and nobody should be stopped on the basis of their race or ethnicity, the Home Office said.