The inquiry conducted by the Health and Safety Executive into the cause of the new Foot and Mouth outbreak has indicated that there is a ‘strong possibility’ that the virus came from the Government-licensed Pirbright complex in Surrey, although it could not say whether it came from the Institute of Animal Health or Merial.

Inspectors are now trying to determine whether the disease may have got out due to drainage problems, or whether it was carried out of a laboratory, either accidentally or deliberately, by Merial employees.

Environment Secretary Hilary Benn has closed all footpaths within the 3km protection zone, and has this morning released a response to the report, on the Department for Environment, Food and Rural Affairs (Defra) website. It reads: ‘Release by human movement – which the report describes as a real possibility ? will now be investigated further as a matter of urgency. This will involve further interviews with personnel at the site.’

However, the US-owned pharmaceutical company Merial has denied all responsibility, saying today: ‘We have conducted intensive internal investigations and, as a result, continue to have complete confidence in our processes and procedures? To date, we have not been able to establish any evidence that the virus may have been transported out of our centre by humans.’

The president of the National Farmers’ Union, Peter Kendall told the BBC’s Newsnight programme that the union was considering legal action, as farmers are already losing considerable amounts of money due to the transport and export bans that are currently in place.