The event marks the start of the carnival

About 7,000 people are expected to watch the Panorama at Horniman's Pleasance in which nine bands compete for the title of Notting Hill Carnival Champions of Steel.

A spokesman for London Notting Hill Carnival Ltd, who is organising the event, said: "The bands will be judged on style, acoustics and how the music is played.

"Today is all about music."

Youngsters will parade their costumes along the carnival route and play music on the Steel Pans on Sunday for Children's Day.

'Relax on Tuesday'

Police are targeting suspected troublemakers in an attempt to make sure this year's carnival runs smoothly.

Metropolitan Police Deputy Assistant Commissioner Andy Trotter told BBC News 17 people across the city had already been arrested and another 80 had been sent letters warning them to stay at home.

The letters said: "We know who you are and what you look like ... We don't think it's a good idea for you to go to carnival," he added.

Officers were delivering the letters by hand and speaking to the recipients, Mr Trotter told BBC News.

"If they do come we have a good chance of picking them up, putting some surveillance behind them and dealing with them," he told BBC News.

The Metropolitan Police has been preparing throughout the year for the annual event which last year cost them about �5m.

Mr Trotter said the bill for this year's police operation was expected to be the same, and he hoped the arrests and other preparations would mean there was even less trouble, especially with 9,750 police officers on duty.

"We will only relax on Tuesday morning," Mr Trotter said.