The death of Kiyan Prince has fuelled fears of a worsening knife culture and prompted fresh demands for heightened security in schools.
Tributes to Kiyan Prince have been laid outside his school
The 15-year-old was stabbed in front of pupils and staff outside his school in Edgware, north-west London.
The killing is the latest in a string of high-profile attacks which campaigners see as evidence of a worsening knife culture in the UK.
These include the death last week of a police special constable jut a few miles away in Wembley and the stabbing of 14-year-old Luke Walmsley, by a fellow pupil at a school in Lincolnshire in 2003.
More police patrols
Police have stepped up high-visibility patrols in Edgware area since the latest attack, which came just a week before the launch of a national knife amnesty.
Social Exclusion Minister Hilary Armstrong has also pledged more powers to allow schools to screen students for weapons.
And officers have visited almost every secondary school in London over the past five months in a bid to educate pupils about the dangers of knives.
But as Kiyan's friends and relatives try to come to terms with his death, a growing chorus of voices is calling for tougher action to keep weapons away from schools.
Caroline Brown, whose son and daughter attend Kiyan's school, has called for the introduction of airport-style weapons screening to prevent similar attacks.
"I think a metal detector should be put in every single school door.
"I'm going to be frightened to let my kids come to school in case it happens again... because you know not every kid's perfect, every kid's frightened, " she said.
There are "some kids out there that do carry weapons", she added.
Dee Edwards, of campaign group Mothers Against Murder and Aggression, said she used to oppose the use of scanners in schools but had now changed her mind.
She told BBC News: "I used to say, 'No, let's not go the way of America,' but now I think we've got to try them. I think that's the way we've got to go."
But she said better education and tougher enforcement by the courts were the key to stopping young people from carrying knives.
A national knives amnesty begins next week
She said: "The first thing we need to do is a massive education programme across the whole country because there is no real deterrent. And we need to punish young people who carry weapons properly.
"There were 88 knife-related incidents in schools last year and I know that sounds like a drop in the ocean but it's 88 too many.
"We have a weapons culture in this country and kids think nothing about picking up a weapon because they know nine times out of 10 the lawyers are going to get them off lightly."
She said there was "fantastic" work being done in some parts of the country with hard-hitting campaigns to educate young people about the potential consequences of carrying weapons but that more money needed to be pumped into it.
On Saturday Minister for Social Exclusion, Hilary Armstrong said the government has planned a range of measures to tackle knife crime.
"This week the government is introducing a knife amnesty to encourage people to hand in weapons that they shouldn't have, " she told BBC News 24.
"But also, we are, through the Education Bill this week, going to be giving schools much more ability to actually screen and tackle any young person who's going into school with a weapon."
Chief Superintendent Mark Ricketts, borough commander for Barnet, told BBC News Thursday's attack was symptomatic of a growing trend.
While knives had once been something of a "fashion accessory", they were now starting to be something people were "prepared to use".
He said: "Maybe we need to start looking at making some rather extraordinary decisions.
"Maybe search arches, search wands, the sort of thing you would see at airports."
Scanners have already been introduced at a school in Tottenham, just a few miles away from where Kiyan was attacked.
But the leader of Barnet council, which covers Edgware, Mike Frier said the council was reluctant to introduce heavy security.
Mike Frier said: "We have to remind ourselves that schools are not fortresses and they are places of education and we need to try and make sure that our schools stay safe and they are still schools at the end of the day.
"I don't want to turn Barnet schools into fortresses."
Commander Alfred Hitchcock, who is heading the Met Police's fight against knife crime in London, said schools did need to improve security.
He told BBC News there had been a perception that if a school chool which took measures to keep out knives it must mean that school had a weapons problem.
He said: "We need to turn that entire argument around and say the schools that are active, that work with the police service and do all of those things are actually the schools that are creating a safe learning environment, doing something very good for their school environment and we should support it."
Schools minister Jim Knight said his department took the problem of knives in schools "very seriously".
But he said the question of whether to introduce knife scanners in schools would require careful thought.
"I think we shouldn't on the back of one appalling incident - and I know there have been others - rush to take measures.
"We need to reflect properly on this, and on a risk-based basis," he told a London radio station.
He said measures were planned under the Violent Crime Reduction Bill to clamp down on knife crime in schools, with extra powers for police to carry out speculative searches.