A man in his 20s has died and two others are in hospital following a "large group fight involving knives" in south London early on Sunday morning.
Emergency services, including the air ambulance, were called to Wandsworth Road near the junction with Lavender Hill in Lambeth just after 04:00 BST to reports of a stabbing.
The man was pronounced dead at the scene while paramedics took another man to a major trauma centre and another to hospital.
No arrests have been made and the police investigation is ongoing, the Met Police said.
Officers are working to inform the man's next of kin that he has died.
They are also awaiting an update on the condition of the man who was taken to the major trauma hospital.
The third person, also a man in his 20s, was treated for injuries that were not deemed to be life threatening.
At the scene, BBC reporter Liz Jackson said: "At least half a dozen double decker buses have stopped in front of several lines of police tape at what is usually a busy crossroads in between Clapham Common and Clapham Junction.
"The area is eerily quiet when it would usually be bustling with locals on their way to restaurants and local parks, or to pick up groceries from the small Tesco or Sainsburys branches at the road junction.
"Behind the cordon, several forensics officers in blue protective suits crouch down to take crime scene photos including on the road, of the bins and of the street by the entrance to the Tesco.
"Pedestrians passing through are stopped by police and turned away, and some gather near the scene to discuss their shock at what happened here, but at this stage no-one knows the full details of how the incident unfolded."
Local Conservative Wandsworth councillors Tom Pridham and Jonathan Cook issued a joint statement following the triple stabbing.
"As local councillors we are both shocked by this tragic incident and would urge anyone with information to contact the police," they said.
'Take action'
It is not yet clear what knife was used in the Wandsworth stabbing, but the death comes a few days after
new legislation came in to force making it illegal to possess “zombie-style” knives and machetes in England and Wales.
On Sunday, Labour MP for Barking, Nesil Caliskan, told
BBC Politics London knife crime was "an issue that was serious across the capital and the country".
"It is high time we took some action on it," she said.
City Hall's Tory leader Neil Garratt said the new legislation was a "positive step".
"My thought on going after knives themselves is that it is a law of diminishing returns," Mr Garratt added.
"The best outcomes will come in turning young people's lives around so they don't want to be carrying a knife and feel they have to protect themselves."
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