Notting Hill Carnival risks mirroring a "Hillsborough-scale tragedy" unless overcrowding and crime issues are tackled, police have warned.
A report published by the London Assembly Police and Crime Committee states the event has reached a "tipping point" and needs to be re-examined to ensure it remains safe.
With more than a million visitors packing the streets during the west London event, one of the main risks is overcrowding, made worse by attendance figures and its location, the report claims.
It highlights how crushing has occurred in Ladbroke Grove, with officers having to dive in a pull children and adults who were suffering crowd distress when the parade and support vehicles pushed people to the side.
It points out how the safety barriers collapsed on "two or three occasions" on All Saints Road, owing to the number of people attending the static sound systems in that area.
The ability of the emergency services to respond to a significant incident is also impacted by crowd levels and geography, the report said.
Metropolitan Police Commander Dave Musker set out his concerns to the Police and Crime Committee in November, when he warned of the risk of "Hillsborough-scale tragedy". The report concluded it "would be foolish to ignore" such comments.
With his points contained within the report, he said that if there was a major incident in the middle of the event, "it would be extremely challenging to deal with".
He said: "Each year - and last year was no exception - we came exceptionally close to a major catastrophic failure of public safety where members of the public would face serious injury."
During the August bank holiday celebration, 6,000 Met officers were deployed on the Sunday and 7,000 on the Monday, with an annual bill of policing the event costing £7 million.
The report states that concern about the level of crime at the carnival is "nothing new", but adds: "We are now seeing a rise in more serious and violent crimes: this year four stabbings almost became murders."
In 2010, there were 343 offences recorded on the Sunday and Monday, with this figure increasing to 396 in 2016 - a rise of 15%.
For possession of weapons, there were 90 arrests last year, up from 57 the previous year, and more than 15 reports of violent injuries involving a knife or blade.
And across the Sunday and Monday, there was an 86% increase in violence against persons - up from 81 incidents in 2010 to 151 last year.
Chairman of the Police and Crime Committee, Steve O'Connell, said more than 400 arrests were made at the carnival last year and that arrangements for crime reduction need to be improved.
"Any large-scale event will experience disorder, but worryingly violent incidents, including a large number of knife attacks, appear to be on the rise," he said.
"But my overriding concern, having listened to the organisations involved in running carnival, is the very real risk to public safety. We must not shut our ears to the concerns being raised."
It is organised by the London Notting Hill Carnival Enterprises Trust (LNHCET), a group London Assembly Police and Crime Committee have said is run by volunteers with little staffing or resource.
Mr O'Connell said that it "cannot be right that the group organising one of London's most high-profile events is staffed by volunteers and is not receiving the support it needs".
The report recommends the city's mayor should help put LNHCET on a more formal and financially sustainable footing - giving it greater responsibility and ownership of the event.
It said the mayor, in partnership with LNHCET, should examine the evidence base for change and consider options, including re-routing the parade or moving elements of the carnival to improve crowd management and safety.
Sophie Linden, the deputy mayor for policing and crime, said: "Frontline police officers and stewards work extremely hard to keep carnival-goers safe in what are often difficult and testing circumstances.
"Every year following the festival, London Notting Hill Carnival Enterprise Trust, the Mayor's Office, the Met police, TfL, The Royal Borough of Kensington and Chelsea, Westminster City Council and the Arts Council look again at how we can keep the event safe, enjoyable and sustainable.
"There are some specific concerns this group are looking to address this year, and all members, including the Met police, wanted to appoint independent experts to give guidance on crowd dynamics and control. Together, they have commissioned a study to understand what more can be done to keep revellers safe, given the huge numbers who take part."