About 12,400 police officers will be on duty for Notting Hill Carnival, with knife arches deployed at key points to deter violence.
More than one million revellers are expected at Europe’s largest street party, with crowds almost certainly boosted by the heatwave forecast for the bank holiday weekend.
Police will respond to incidents and conduct stop and searches amid fears surrounding London’s violent crime epidemic.
Last year, there were 373 arrests for a range of offences, including 156 over drugs, 69 for offensive weapons and nine for sexual offences. This compared with 301 for 2017 and 454 the year before.
Superintendent Elisabeth Chapple said: “As always, we have worked very closely with the event organisers to ensure a safe environment where people from across the world can come and enjoy themselves.” Commander Dave Musker said officers will “proactively target” offenders.