Leading article: More trouble on the farm

There was a depressing air of inevitability about the weekend's news that the UK's first case of bluetongue had been identified. All summer, the virus has been creeping ever closer, through Germany, France, and the Netherlands. There have been 3,000 cases in northern Europe since July.

Farmers' hopes that the Channel and the North Sea would prove enough of a natural barrier always seemed rather optimistic, especially given that the disease is spread by midges. In certain weather conditions these tiny insects can travel formidable distances over water. It is likely that we are seeing another malign consequence of climate change. Bluetongue has been a blight in Africa for many years. Warmer temperatures in Europe have now encouraged the midges to migrate north, bringing the disease with them. We must hope that the sick animal found on a rare-breed cattle farm in Suffolk proves to be an isolated case, and that bluetongue will not become a full-scale outbreak.

There are some grounds for optimism. Given that bluetongue was always likely to reach these shores, the timing could be considered rather fortunate. Winter is coming, and the colder weather may well kill off the adult midges that spread the disease. And there is some comfort to be taken from the fact that cattle movement restrictions are already in place because of the alarm over foot-and-mouth. It is also a bonus that farmers will already be on the lookout for flu-like symptoms among their livestock, again because of foot-and-mouth. Any new cases of bluetongue should be quickly spotted.

But there can be no getting away from the fact that this has the potential to be a tremendous economic blow to UK farmers. Britain has some of the densest populations of sheep and cattle in the world. An outbreak could spread like wildfire. We should also bear in mind that buckets of disinfectant at the farm gate are of no use against this disease.

An outbreak would mean the slaughter of infected animals. It is not only farmers who would suffer because of this. It would also hurt consumers through higher meat and dairy prices. The consequences for tourism would be profound, too. The gravest danger is that the virus will become established here, as it has in parts of Europe. When this happens, there is no failsafe way of protecting animals. No vaccines are yet available for the northern European strain of the virus. And by the time they are, it could be too late. The fate of British agriculture once again rests on a knife edge.