This highly infectious viral disease, easily spread on vehicles, clothing and even the wind, is endemic in much of the Third World. But North America, western Europe and Australasia have generally been successful in excluding it, by prohibiting imports of uncooked meat and livestock from foot-and-mouth countries and slaughtering infected and implicated herds when outbreaks do occur.

The policy has been relatively successful in Britain - the last major outbreak was over 30 years ago.

But the speed with which the current outbreak has spread has astounded everyone. It has come only six months after an outbreak of classical swine fever, another whole-herd slaughter policy disease that had not been seen in the country for 14 years. The question now being asked is whether this is a coincidence or a trend.

The farmer believed to be the source of the outbreak was a licensed swill feeder, feeding the cooked refuse from restaurants, schools and other institutions to his pigs. While nothing has been proved, an obvious potential source of the infection is illegally imported meat, which found its way into the swill and did not get cooked sufficiently to kill the foot-and-mouth virus.

The spread of the disease has been mainly by sheep, which are moved frequently at this time of year as cheap sources of feed such as crop aftermaths are sought.

But something this serious should not be blamed entirely on the actions or inactions of individual farmers.

Suggestions will be made that the disease would never have entered the country, if there had been proper import controls. Such controls can, of course, never be absolute.

A more effective defence is a robust industry, one that can afford not to cut corners when it comes to such things as “cheap” feed. With net farm income a tenth of what it was five years ago and most of the livestock sector running in the red, the internal line of defence looks and has been proven very fragile.

For CBC commentary, I'm David Walker, an agricultural economist, at Lodge Farm Postwick in Broadland Norfolk, England.

David Walker was senior economist for Home-Grown Cereals Authority in London and previously was executive director of the Alberta Grain Commission. His opinions on British and European agricultural issues can be found at www.openi.co.uk/