Inspectors from the Health and Safety Executive expect to announce within the next 36 hours whether or not the publicly funded Institute for Animal Health research facility Pirbright or privately owned Merial sites could have been the source of the recent Foot and Mouth outbreak.

It was revealed on Sunday that the strain of the disease that was found at the farm in Surrey was the same strain that was being used at two Pirbright facilities four miles away. However, inspectors are now focusing their investigations on the nearby US-owned pharmaceutical company Merial, which develops vaccines, as it had used the strain more recently. However, both sites deny all responsibility.

David Biland, managing director of Merial, says that vaccine production has been suspended and staff will be available to help with enquiries. ?To date,? he told the BBC earlier today, ?investigations continue to show no breach in our procedures.?

Foot and Mouth was discovered at the weekend at a farm in Normandy, Surrey. A second infected cow was then discovered at a second site that was owned by the same farm and, as a result of this, Debby Reynolds, the Government?s Chief Veterinary Officer, has ordered a precautionary cull at a nearby second farm in Elstead, Surrey. As of Sunday evening, 120 cattle from the three sites had been slaughtered. Debby Reynolds has now extended the protection zone to prevent further outbreak.

David Fursdon, President of the Country Land and Business Association (CLA) has issued a statement, saying: ?The news that the type of foot and mouth virus found in Surrey could have come from the Institute of Animal Health laboratory at Pirbright or Merial Animal Health Ltd is a mixed blessing. It is good as steps were quickly taken to investigate the source of the infection ? something we have stressed repeatedly – but it is bad as it raises serious questions about biosecurity at Pirbright. We therefore welcome the immediate steps taken to instigate an independent review into biosecurity arrangements at both sites.?

Gordon Brown has cut short his holiday in Dorset to urge people not to let this affect UK tourism: ?While there is a national ban on the movement of pigs, cattle and sheep, people are free ? outside the protected zone ? to continue with their holidays and continue walking around the countryside.?

However, approximately 111,000 farms have already been affected by the movement ban, including 10 million cattle, 23 million sheep and 5 million pigs, and many more are extremely nervous of the disease that, when it broke out in 2001, led to the destruction of approximately 10 million animals at a cost of almost £8.5bn.