More than one million revellers are expected to descend on the capital over the next two days for Europe's biggest street festival - the Notting Hill Carnival.
Dancers wearing vibrant costumes will parade along the packed three-and-a-half mile route in west London from 9am today to the sounds of traditional steel drums.
The lines of colourful floats will be accompanied by more than 40 static sound systems and scores of Caribbean food stalls during the event, which is now in its 48th year.
A massive security operation will also be in force with thousands of police officers set to take to the streets.
A total of 5,000 officers will be on duty today, followed by 7,000 officers on Monday, Scotland Yard said.
Police have already arrested 27 people during an operation to crack down on suspected troublemakers ahead of the carnival.
Police said screenings will take place at entrances to the carnival to scan for weapons.
Last year's event was marred after a 20-year-old man was stabbed towards the end of the festival.
During this year's security operation, police cadets will hand out free maps at tube stations on both days of the carnival in an effort to reduce mobile phone thefts.
Mobile users have been warned thieves have previously snatched devices when people have used their phones to search for directions.