Government vets are investigating possible foot and mouth outbreaks on farms in Kent and Surrey, it emerged today.

In Kent, a temporary control zone has been put in place in the Romney Marsh area around Dymchurch and Littlestone-on-Sea, although the exact location of the farm has not been released.

The zone was erected as a "precaution" after the farmer reported a sickness in his animals.

In Surrey, a new foot and mouth disease temporary control zone has been set up around Chessington World of Adventures, which lies outside the existing surveillance zone.

The zoo at Chessington, which celebrated its 75th anniversary last year, boasts 97 species of animal, including lemurs, skunks, penguins, otters, monkeys, pygmy goats, pot bellied pigs and sheep.

A Chessington spokeswoman said: "Chessington World of Adventures & Zoo can confirm that following the daily health checks carried out on all our animals, a vet was called this morning to examine one of the Zoo's sheep.

"As a precautionary measure and because of the high state of alert currently in place due to the recent cases of foot and mouth disease, it was decided to immediately check all our cloven hoof stock for any signs of disease and do necessary tests; and as part of our standard precautionary procedures Defra was also alerted."

The Children's Zoo and Creature Features areas of the Park, where the hoofed animals are located, were both closed to the public at the beginning of the foot and mouth outbreak earlier this month, she said.

Debby Reynolds, the Government's chief vet, said test results from the farm in Kent were expected later today or early tomorrow.

If the disease is confirmed it would be a massive blow to Britain's farmers, who had hoped that the outbreak was under control and confined to two farms in Surrey, where it was first detected.

A spokeswoman for Defra said it was "not unusual" to put a temporary control zone in place.

The zones allow Defra to close land and footpaths to the public.

"We're being ultra-cautious at this point," she said. "There's a continuing need for relentless vigilance in response to foot and mouth disease."

The first outbreak was confirmed on cattle belonging to Roger Pride in fields in Normandy near Guildford, Surrey, on August 3, prompting Defra to impose a 3km "protection zone" and a 10km "surveillance zone".

A nationwide ban on the movements of all sheep, cattle and pigs was put in place and the affected animals were culled the following day.

The second outbreak was confirmed on August 6 in cattle owned by John Gunner within the exclusion zone in the village of Normandy.

On August 8, Chief Veterinary Officer Debby Reynolds said the movement of animals directly between farms and slaughterhouses would be permitted under licence, but the ban on all other movements of susceptible animals remained in force.

Livestock culled on a third farm - John Emerson's at Hunts Hill in Normandy - within the protection area were found not to have foot and mouth disease.

Vets were called to Manor Farm in Wotton, near Dorking, Surrey, on Thursday after calves began exhibiting signs of a virus - runny noses and swollen eyes.

On Saturday, Defra announced that tests on the animals had proved negative and the temporary 3km control zone set up around the farm had been lifted.

A spokesman for the National Farmers' Union said: "This is a case of a very vigilant farmer who's called in vets at the slightest sign there might be something wrong with his animals.

"We are hopeful that this will be the same situation as Dorking."

The Health and Safety Executive (HSE) is investigating what caused the original outbreak. In the frame are two research laboratories - one Government-run, the other private - at Pirbright, four miles from the first infected herd.