The Government’s top animal expert says farmers must continue to keep a close eye on their livestock, despite the news that a suspected case outside the original infection area proved negative.

The Department for Environment, Food and Rural Affairs (Defra) yesterday lifted the control zone it had set up around a farm at Wotton, near Dorking in Surrey. Tests for foot-and-mouth disease virus found no infection. The animals had been reported by their owner because they displayed similar symptoms.

Chief Veterinary Officer Debby Reynolds said yesterday: “This is day eight of the foot and mouth outbreak. I must stress the need for relentless vigilance. It is crucial that all animal keepers continue to check their animals regularly and practice the highest possible levels of biosecurity.

“There is a substantial operation on the ground to prevent the spread of this disease and we are seeing a tremendous response. I would like to thank all of those involved.”

However, a more optimistic note was struck by microbiologist Prof Hugh Pennington, who told the BBC he believed it highly unlikely there would be any further outbreaks of the virus.

Speaking on BBC News 24, he said: “I think by the end of next week if we’ve seen no more cases, I think we can say it's highly, highly, highly, highly unlikely that there will be any more cases; not before then.” That's enough highlys, we think.

Defra and ministers have been at pains to stress the countryside remains open to walkers, climbers and cyclists, despite the erection of some illegal signs and footpath blockages by a few farmers. Only in the protection zone around the two farms in Surrey where confirmed cases have occurred are rights-of-way legally closed.

If the threat of a wider outbreak does recede, the outdoor and tourism industry will breathe a huge sigh of relief. The virtual shutdown of the countryside throughout the UK, with a ban on the use of footpaths and bridleways, was estimated to have cost £9bn.

A general restriction on moving cattle, sheep, pigs and goats remains in place, with exceptions for animals going straight to slaughter or for milking.