It will be a cruel irony if those responsible for stopping animal diseases such as foot-and-mouth turn out to be responsible for the current outbreak in Surrey. Yesterday, the inquiry into the cause of the outbreak was focused on facilities at Pirbright where the government's own Institute for Animal Health shares a site with the private pharmaceutical company Merial Animal Health. This follows confirmation that the strain implicated in the outbreak at Wolford farm, less than five miles away, is identical to that used in animal vaccine.

Though the most likely source is the Merial plant, this is only marginally less embarrassing for the government than if it turns out to be the dilapidated government research facility next door that was identified as overdue for replacement following the disastrous 2001 foot-and-mouth outbreak. The Merial plant, too, is licensed by the government and, if it is indeed the source, there are now questions to be answered about how such a serious breach of biosecurity could have happened and whether there is any possibility that it could have been deliberate. That is why it is essential the government review led by Professor Brian Spratt must not only be independent but also untramelled by limits on its terms of reference.

The government's rapid and well co-ordinated response to this outbreak is an encouraging indication that lessons have been learned since 2001 but, given that veterinary officials must have known of the proximity of Pirbright to the infected farm, it is mystifying that these facilities were not included in the original exclusion zone, declared on Friday. And given that the disease has a normal incubation period of three to six days, it should also worry us that the last batch of foot-and-mouth vaccine produced by Merial was on July 16. Has the disease been spread unwittingly to other areas of the country by cattle movements in the interim?

Until we know the answer to that question, a ban on livestock exports and movements throughout the UK mainland is essential, despite the inconvenience to farmers, livestock auctions, abattoirs and agricultural shows. In 2001, the disease had spread to 57 farms before the movement ban was imposed. As a result, the worst outbreak in British history cost an estimated £8bn and the lives of six million livestock. It is to be hoped that decisive timely action can contain this outbreak and its financial consequences.

However, it is also important that the response is proportionate, especially once the disease has been eradicated. This applies particularly to the European Union, where actions are sometimes heavy-handed and unduly influenced by the self-interest of other EU members. Exports of British beef were resumed only in May 2006, a decade after being banned following the BSE crisis. This was unjustified. Moreover, if the current outbreak is contained in the south of England, there is no reason why Scotland should not request exemption from the export restrictions.

Meanwhile, the British public can play its part in minimising the impact on the rural economy by continuing to consume dairy products, visit the countryside and attend agricultural shows. By suggesting the countryside was closed to the public in 2001, the government deepened the impact of the crisis, which cost rural tourism an estimated £5bn.