The move comes after at least 48 people have been stabbed to death this year, described by some as a "national emergency".
Sunday 31 March 2019 07:07, UK
Police are being given more powers to use controversial stop and search tactics in their fight against knife crime.
Thousands more police officers will now be able to authorise enhanced search activity after the home secretary relaxed rules allowing officers at a lower level of seniority to use the tactic.
Dozens of people stabbed to death this year
Sajid Javid has also made it simpler for police to use Section 60, a blanket power which enables officers to 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.
The changes will apply initially to London and the six other forces worst affected by knife crime. They include West Midlands, Merseyside, South Yorkshire, West Yorkshire, South Wales and Greater Manchester.
Critics have claimed stop and search unfairly targets young black men.
At its height in 2008, more than 1.5 million people were stopped and searched in England and Wales.
Changes brought in by Theresa May when she was home secretary, raised the threshold for use of the power and led to a dramatic reduction, with 282,000 people stopped and searched last year.
The changes announced by Mr Javid do not amount to a full reversal of the policies introduced under Mrs May, but it is a sign that the home secretary has been listening to the concerns of senior officers, who believe the tactic is a vital tool in their armoury.
The home secretary was shown around a stop and search operation at an underground station in Islington, north London.
Latest statistics still show that young black men are nine times more like than young white men to be stopped and searched.
Dozens of officers used spotter teams and portable metal detecting knife arches to search people at Angel Tube station.
Within minutes, officers stopped one young man and recovered a knife, with a three-and-half inch spring assisted blade. He was arrested and the weapon seized as evidence.
Scotland Yard's deputy commissioner Sir Stephen House told Sky News: "I think we're in a new era with stop and search. I think a lot of that is down to better training for our officers.
"We understand the tactic can be difficult for some people. But I think people understand that in London and other urban centres, it's a vital tool to prevent crime and take weapons like knives off the streets.
"We also deploy our officers, now some 20,000, with body-worn video cameras and in around 90% of stop and searches the cameras are on. I think that gives the officers confidence, but it should also give members of the public confidence as well.
"We now get remarkably few complaints from the public about stop and search. I think most people in London realise it really is a tool that's there to be used properly, to be used effectively and when it is used properly and effectively, it keeps people safe in London."
Latest statistics still show that young black men are nine times more likely than young white men to be stopped and searched.
The deputy commissioner said: "We monitor those statistics along with the mayor's office, but the fact is that the people that are dying on the streets are also disproportionately young black males.
"They're the ones who are the victims. Often, they are the ones who are the offenders as well. So we believe we are acting proportionately to deal with the problem that Londoners face."
Kheron Gilpin, who volunteers in outreach work and other community projects in south London, said that proper training is vital if police are to gain the trust of young people.
He said: "I've been stopped on many occasions and a number of times it's been very unpleasant and some other times, it's been a pleasant interaction.
"Too many of my experiences and stories I've heard, have been very unpleasant, which leads to a lot of tension between the police and young people, to the point where you have young innocent civilians running away from the police just so they're no subjected to an unpleasant stop and search."
There were 285 homicides where knives were used in the year to March 2018 - the highest number since records began in 1946.