In July, almost unnoticed by the national press, a deadly bird virus arrived on a pheasant farm in Surrey. Experts from the Department for the Environment, Food and Rural Affairs (Defra) identified Newcastle disease, a virus usually mortal to turkeys and geese but not humans, in a flock of 9,000 pheasant chicks imported from France ahead of the shooting season. Within hours of the diagnosis, veterinary experts had swung into action, throwing up a 3km exclusion zone around the farm near Cobham and culling 10,000 birds. The carcasses were burned and premises cleaned to stop the virus escaping. It was four weeks before Defra's Veterinary Exotic Diseases Division felt it was safe for poultry move virus has reached Turkey, similar emergency plans are being readied by officials from Defra and other agencies. The scenario they are preparing for is that the H5Nlvirns, which so far has led to the culling of billions of chickens in south-east Asia and 60 human deaths, will soon arrive on these shores. What happens next depends on where the outbreak occurs, whether it can be contained, and most important of all—whether it mutates to become infectious between people. So far, only poultry workers or those directly exposed to chicken faeces or blood are thought to be at risk, though direct human-to-human transmission cannot be ruled out. 'Every time a new person gets infected with the virus there is a small chance that person will trigger a pandemic,' said Neil Ferguson, a scientist at Imperial College, who has been running simulations on what might happen were H5N1 to reach Britain. 'It's a very small chance, probably 1 in a 1,000, 1 in 10,00O or less.' Should diseased birds reach Britain, the first step for veterinary officials would be to contain the outbreak as they did with Newcastle disease. An amber alert would be sounded and samples sent to the Veterinary Laboratory Agency (VLA) in Weybridge, Surrey. If lan Brown, the head of avian virology, there, confirms the cause of death as HSN1, the alert level will be raised to red and a whole series of emergency procedures, from quarantine, restriction of poultry movements to culling, will swing into action. Other agencies, such as the Department of Health—the Health Protection Agency and the Ministry of Defence, would be brought into the loop. In the event that the outbreak cannot be contained, Defra may have to consider mass culling programmes and the possibility of vaccination. At this point, with the risk of the virus spreading to human populations, the Department of Health would appoint a UK national influenza pandemic committee to coordinate the response of hospital trusts and local authorities. The Civil Contingency Secretariat (CCS) of the Cabinet will also be alerted and Cobra, the emergency committee which coordinates Whitehall's response to terrorism, readied for a possible breakdown in civil order. The Department of Health's pandemic preparedness plan published in March envisages as many as 54,000 Britons dying in the first few months of a flu pandemic. But in June, CCS officials warned that that could be an underestimate. The more likely figure, they said, was 700,000—a projection the Department of Health is expected to take on board when it updates its pandemic plan later this month. In the most serious case, officials estimate there would be as many death sin the 12 weeks of an epidemic as there usually are in a year. At the peak of the pandemic, 19,000 people would require hospital beds, prompting councils to requisition schools to accommodate the sick. To treat the dying, the government would begin drawing down its stockpiles of Tamiflu (药名), an anti-viral drug that treats flu. But with only 14m courses, enough for a quarter of the population, likely to be available, sooner or later rationing would have to be imposed, with health professionals and essential civil servants the first in line. The g