The Notting Hill Carnival takes place on the August Bank Holiday weekend
Stop and search measures will be in use at this year's Notting Hill Carnival, with thousands of police on duty.
Technology to recognise number plates and screening wands to check for concealed weapons will also be used.
About 1.5m people are expected to join Europe's biggest street party from 29 to 31 August.
The Metropolitan Police said their tactics to stop people with weapons getting in to the event have been widely supported by carnival goers.
Last year the special Operation Razorback unit made 11 arrests, seizing drugs, cash, a stolen car, knives and a loaded gun.
Ch Supt Mick Johnson said: "It's important to remember that crime rates do remain relatively low at Carnival, especially given the thousands of people who attend.
"Carnival is a fantastic, colourful event that unites the community in celebration - let's work together to make sure it remains that way."
British Transport Police will have extra officers patrolling stations and mobile metal detection arches will be used when necessary.
Alcohol is already banned on the Tube network.