Surrey and Sussex officers sent to aid Met Police
Specialist police officers from Sussex have been sent to London for a second day after three nights of rioting.
The force said about 50 officers were en route to the capital to support the Metropolitan Police, which will have 16,000 officers on duty.
A force spokesman said the deployment would not be at the "expense of policing in Sussex".
On Monday, officers and helicopter support from Surrey and Sussex were sent to London to help tackle rioting.
Riot police from Surrey were on duty in the Tottenham area of north London, from about 15:00 BST on Monday.
Another team of officers was deployed in Croydon at about 03:00 BST following a request from the Met Police.
Sussex Police said a number of specially-trained officers were also giving assistance.
At 08:30 BST on Tuesday morning the force said all the officers had returned safely to the county.
An extra 1,700 police officers were deployed in London, where shops were looted and buildings were set alight during a third night of violence.
The Met Police said at least 400 people had been arrested following the riots across the city.
Some of the people who have been arrested have been transferred to cells at Guildford police station.
Surrey Police temporary assistant chief constable Charlie Doyle said: "We have well rehearsed plans for supplying mutual aid to other forces to support them during such exceptional events but our priority remains the safety of Surrey residents.
"Whilst there have been no significant incidents of public disorder in the county, we will continue to monitor the situation and ensure we have suitable resources to deal with any incidents that arise."
A spokesman for Sussex Police said: "It is important that we do all we can to prevent the sad scenes that we are seeing elsewhere.
"We would appeal to everyone of all ages and from all walks of life to disregard the rumour-mongering that is unnecessarily raising tensions and fears in some Sussex communities."
Officers from seven other police forces have also been drafted in to aid the Met Police.
The Carling Cup game between Crystal Palace and Crawley Town at Selhurst Park on Tuesday evening has been postponed.
Southeastern trains and Southern Railway said their services had not been affected by the rioting in London.