Notting-Hill Carnival poses a “real risk to public safety” and in 2016 saw four stabbings so serious the victims nearly died, according to a report.
The event – at which 450 arrests were made last year – must be made safer, London’s mayor has been warned.
It is one of Europe’s largest carnivals, with up to 7,000 police on duty, 50,000 performers and a million visitors.
The London Assembly Police and Crime Committee said overcrowding and a rise in violent crime were the main issues.
The 2016 carnival was policed by 6,000 Met officers on Saturday and Sunday and 7,000 officers on August bank holiday Monday.
More than 400 people were arrested at Carnival in 2016, the highest since 2008. Police said they had seized 90 offensive weapons while patrolling the event.
In 2015, officers made about 300 arrests for a range of offences during the festival, including assault, criminal damage, public order offences and theft.
In its latest report, the London Assembly Police and Crime Committee said the annual event urgently needed rethinking.
“Public concern about the level of crime at carnival is nothing new. But we are now seeing a rise in more serious and violent crimes: last year, four stabbings almost became murders,” the report said.
The report revealed 396 crimes were recorded at the 2016 carnival, up from 343 in 2010, with offences of violence against people rising from 81 to 151 in the same period.
“Traditionally, the vast majority of offences have been related to theft and drugs. The number of violent crimes, however, is rising.”