Professor Hugh Pennington interviewed on BBC News 24 gives as his opinion that the source virus is identical to that in vaccine work being done at Pirbright and very possibly excaped from there. The latest statement by DEFRA :"The FMD strain found in Surrey is not one currently known to be recently found in animals. It is most similar to strains used in international diagnostic laboratories and in vaccine production, including at the Pirbright site shared by the Institute of Animal Health (IAH) and Merial Animal Health Ltd, a pharmaceutical company. The present indications are that this strain is a 01 BFS67 - like virus, isolated in the 1967 Foot and Mouth Disease outbreak in Great Britain.
This strain is present at the IAH and was used in a batch manufactured in July 2007 by the Merial facility. On a precautionary basis Merial has agreed to voluntarily halt vaccine production.
You might also read this cheery article by a former president of the RCVS:
March; lambs leaping among the shining tussocks of young grass. But it was not so just five years ago.
In the name of veterinary disease control, we were about to embark on the greatest unnecessary slaughter of healthy animals in the history of our profession. It cost £10 - 12 billion and involved, to the European Parliament, the slaughter of 10 million animals.
Since fewer than 25 per cent of the pre-emptively culled premises were actually infected, and since the consequent mass killing probably impeded control, the money wasted was of the order of £1 - 2 billion: say £100 per household. That sort of money could have financed the MRC’s research expenditure throughout those five years.