A mother who attended Notting Hill Carnival on Sunday with her child narrowly avoided being killed after she was stabbed, the Metropolitan Police has said.
The 32-year-old remains in a critical condition in hospital.
Deputy Assistant Commissioner Ade Adelekan said Carnival’s family day had been “marred by unacceptable violence”.
About 7,000 officers are patrolling this year’s event, which is expected to attract about one million people across Sunday and Monday.
Issuing an update on Monday morning, the Met said two men had also been stabbed at the west London street festival on Sunday.
A 29-year-old has non life-threatening injuries, while a 24-year-old discharged himself after receiving hospital treatment.
No arrests have been made in relation to the three stabbings.
About 100 arrests have been made for a range of offences including violence with injury, sexual offences and possession of offensive weapons.
Eighteen officers were assaulted, the force added.
A section 60 order, which gives officers additional powers to search suspects, was put in place from Sunday evening until 02:00 BST on Monday.
‘Tired of seeing crime scenes’
Mr Adelekan, who is in charge of the event’s policing operation, said Sunday was supposed to be “family day”.
“We saw the first day of Carnival marred by unacceptable violence,” he said on Monday.
“Three people were stabbed and we only very narrowly avoided a fatality.
“One of those in hospital, a 32-year-old woman whose condition remains critical, was at Carnival with her young child.”
Mr Adelekan appealed for information to help police, but also reiterated the force wanted Carnival to be an event enjoyed.
“We are tired of saying the same words every year,” he said. “We are tired of telling families that their loved ones are seriously injured, or worse. We are tired of seeing crime scenes at Carnival.
“Carnival is a community event and the vast majority of people come to celebrate, to dance, to enjoy music and have a fantastic experience.”
Speaking to the BBC, Commander Charmain Brenyah, the Met’s spokesperson for this year’s event, said the force was “really disappointed that family day ended with violence”.
“This is not what we expected on family day. It is a difficult day for everyone who has come and who is policing the event,” she said.
“We absolutely do not want a repeat of what happened yesterday. We want this to be a peaceful day, a celebration.”
Ahead of this year’s carnival, the Met described it as a fixture in London’s cultural calendar that was also a “challenging event to police with very dense crowds and a regrettable history of a minority of people using it as an opportunity to commit crime, including violence”.
Before the event, Ms Brenyah said that as she had grown up not far from where Carnival takes place, she had “happy memories of the music, costumes, floats and fantastic atmosphere”.
“As a police officer on duty in previous years I’ve seen both the carnival I experienced in my youth, but also the other side of the same event when, later in the day, the atmosphere changes in some parts, with floats and costumes giving way to serious violence.”
She added that in the past two years, one person had been killed, 14 others had been stabbed and more than 125 police officers had been assaulted.
About 500 arrests were made at the carnival during those two years.
“These incidents can’t be downplayed or dismissed,” she said.
“It is for that reason that anyone going to Carnival will see a very significant policing presence.
“We’re there to keep you safe – if you see us say hello – but we’re also there to intervene decisively against those intent on violence.”
Separately, the London Ambulance Service (LAS) said it had 180 extra staff on duty across the event – most will be clinicians who can get to patients in crowded areas on foot or by bike.