So far the latest bird flu outbreak is a crisis only for the farmers whose birds are being culled near Diss. Some discerning buyers may have to source their turkeys elsewhere, but outside the “restricted” zone set up round Redgrave Park the picture is less bleak: farmers and government can derive some comfort from Gressingham Foods' prompt reporting of the outbreak on Sunday and Suffolk County Council's rapid response. The poultry industry can reassure consumers that even in the unlikely event of a bird infected with the H5N1 virus entering the human food chain, proper cooking would kill the virus. And consumers themselves should resist any urge to panic, since H5N1 has yet to mutate into a form that would allow easy humanto-human transmission — a prerequisite for a pandemic. None of this, however, makes a mutation of the virus any less likely in the future, nor the need to prepare for it any less acute.

The global human death toll from avian flu since 2003 is about 300. In all but a handful of cases, the human infection has resulted from close, long-term contact with infected poultry in South-East Asia, and even where it appears that the unmutated H5N1 virus has jumped from human to human this has not been confirmed. Yet the risk of mutation will not go away. On the contrary, it will rise with the prevalence of the virus in domestic and wild bird populations, and with their exposure to humans. There is evidence that it may rise farther when the virus is transmitted first to other livestock, particularly pigs, and when human resistance is already low because of human influenza.

These risk factors can and must be confronted. Within Britain, the most urgent need is for clearer rules for free-range farms. Growing public demand for humane treatment of poultry is a positive development, and most farmers meeting that demand manage responsibly to balance their birds' “freedom” with public health. But ensuring that domestic birds do not mingle with migratory wild flocks, as appears to have happened round an ornamental pond at Redgrave Park, should be a requirement, not a guideline. Secondly, local authorities should be properly equipped to police such requirements. It is absurd, as rural Britain steels itself for yet more culling after this year's outbreaks of foot- and-mouth and bluetongue diseases, that county councils should be facing steep cuts in their animal disease control budgets because funds promised by the Department for Environment, Food and Rural Affairs are unavailable.

South-East Asia remains by far the most likely region in which a human avian flu pandemic would start. This prospect places an urgent obligation on international bodies to back long-term projects to reduce human exposure to infected birds in the region, especially in the millions of smallholdings where humans and poultry have traditionally co-existed.

Meanwhile, Britain should take urgent steps to boost its flu drug supplies. As we report today, plans to double to 30 million the number of stockpiled Tamiflu doses have been approved by health ministers but appear to have been delayed by the Treasury. The larger stockpile would allow preventive use of the antiviral drug for every at-risk household, at a cost of £150 million. Not spending it could prove a disastrous false economy.