Youth workers say they are concerned by a rise in the number of children found with knives.
The mother of a teenager murdered in Croydon is calling for life-saving bleed kits for stab victims to be placed in public spaces.
In August 2016 Andre Aderemi, 19, was chased, beaten and stabbed to death with a sword on a housing estate in Selsdon.
Three of Mr Aderemi's convicted killers were taught by his mother Yemi Hughes.
The 41-year-old is raising money to buy bleed kits to be put in shops and transport hubs so that crucial first aid can be administered before emergency services arrive.
Each pack contains gauze to reduce severe haemorrhaging, a chest seal dressing which allows air to escape the pleural cavity, a tourniquet, gloves and scissors.
Ms Hughes said: "It was the loss of blood due to the number of times he was stabbed that ultimately caused my sons death.
"If the bleeding could have been stopped or stemmed and the oxygen was still able to reach his brain then maybe, just maybe he would have had a better change of survival.
"This is why I believe that public access bleed kits are vital to have in the community."
The number of knife crimes rose by 5% in London, figures released by the Office for National Statistics (ONS) on Thursday showed.
It reflected the rise across England and Wales which were the highest on record last year, up 7% on the previous 12 months and since records began a decade ago.
Police-recorded offences involving a knife or sharp instrument rose to 45,627 for the year to December.
The report said: "Knife or sharp instrument offences continue to be concentrated in metropolitan areas across England and Wales, with around a third (34%) of all offences recorded by the police in London."
The figures also show a 15% rise of homicides recorded by the Metropolitan Police in the last year - to 146 from 127.
Of all recorded homicides last year, 40% involved a knife or sharp instrument, a similar proportion to 2018, according to the data.
Diana Fawcett, chief executive of the charity Victim Support, said: "We are concerned that reports of knife crime and homicide have risen."
Last year, Prime Minister Boris Johnson announced that he would lead a new Cabinet committee looking at ways to tackle crime.