Record numbers of police officers will be on duty across London during the Notting Hill carnival, Scotland Yard has said.

The carnival, which attracts crowds of 1 million people, is taking place this year in "unusual and exceptional" circumstances, said Commander Steve Rodhouse of the Metropolitan police.

Rodhouse, the Met's spokesman for the Notting Hill carnival, confirmed that police numbers would be around 16,000 throughout the Bank Holiday weekend across the capital. The Met is continuing to receive help from outside forces to maintain policing at this figure.

The number of officers on duty at the carnival on Sunday and Monday will be more than ever before. In addition, it is understood police will use Section 60 of the Criminal Justice and Public Order Act 1994, which gives officers powers to stop and search individuals in a designated area without reasonable suspicion that they are about to commit an offence.

On Sunday, the children's carnival, 5,500 police will be on the streets. On Bank Holiday Monday, which attracts the biggest crowds, 6,500 police will be at the event, Rodhouse said.

A reserve of 4,000 additional officers will be available across London to cope with any disturbances in other areas. They will also be complemented by the usual number of borough officers on duty, maintaining the total available at 16,000.

Rodhouse said there was some intelligence from social networking sites and elsewhere that gangs were intent on causing trouble during the carnival.

But this was not on a different scale to previous years and there was no intelligence to suggest gangs of looters were going to target the event, he added.

"Some people believe that we will be diverted from the rest of London due to the carnival, leaving the rest of London without a police presence. This is not the case," said Rodhouse. "To those who want to come and corrupt this magnificent event I would say you are not welcome. The Metropolitan police will do everything in our power to make it as hard as possible for you."

Carnival organisers have decided the street party will start and finish earlier this year to avoid any potential trouble as darkness falls. Chris Boothman, director of the Notting Hill Carnival Ltd, said he supported the policing plans. He said the aim was to finish the parade at 6.30pm so that people would start to clear the area after 7pm.

Pubs and other venues in the area have been asked to close at 9pm and Rodhouse said there had been a positive response.

Thirty-five people have been arrested as part of Operation Razorback, a four-week operation which police say is aimed at clamping down on troublemakers ahead of the event.

Officers from the force's territorial support group have been executing search warrants across the capital as part of the operation.

There had been concerns that this year's carnival would be cancelled because of the unprecedented disorder and looting which took place over four days in London and across the country.

But the acting commissioner of the Met, Tim Godwin, made clear when he appeared before the home affairs select committee that he wanted the carnival to go ahead.