A teenage boy is in a serious condition after being knocked off his bike by a car and repeatedly stabbed in south London.
Metropolitan Police Commissioner Dame Cressida Dick said the 16-year-old had just left home when he was attacked in Brixton on Tuesday evening.
Five weapons, including two Rambo-style knives, two “zombie” knives and a kitchen knife, were recovered from the scene, she added.
The victim, who was knifed “in many different places”, remained in hospital in a serious but stable condition on Wednesday.
Detectives are appealing for a white van driver who may have witnessed the stabbing in Henry Road to come forward.
Detective Inspector Yasser Awad, who is leading the investigation, said: “This violent attack has left a teenage boy in hospital with serious injuries.
“We believe there may be people who saw what happened to him but have not yet come forward.
“The attack took place in a residential area and many people will have been in their homes due to the ongoing lockdown.
“If you heard a commotion or saw anything suspicious, we want to hear from you.
“In particular, we want to speak to the driver of a white van which was on Henry Road between 6.15pm and 6.20pm. We believe the driver may have vital information.”
Dame Cressida told City Hall's police and crime committee on Wednesday that "violent crime is not on the up again" but said there have been "ghastly offences" and "horrible homicides" at the start of 2021.
"There have been some stabbings of young people. I think that's a sign of some gang tensions. We're working really hard to reduce those crimes," she said.
Dame Cressida highlighted "fantastic results" in tackling county lines drugs gangs, with more than 1,000 charges brought since November 2019 with other forces across the UK and 324 deal lines closed.
She said London’s Metropolitan Police also seized 43 firearms between February 7 and 18, including an Uzi submachine gun, a sawn-off pump action shotgun and self-loading pistols.
"I am not suggesting that we can see a trend at the moment of violence going up," she said.
"Of course, I fully expect that there will be an increase in certain types of crimes, however well we do our job, when we do begin to ease lockdown measures."
Additional reporting by PA