After mad cow disease and foot and mouth, livestock farmers are bracing themselves for another major animal health problem.
Scientists are warning that a hot summer could bring the bluetongue virus to the UK for the first time ever, with disastrous consequences for farmers.
Efforts to prevent the disease spreading would stop animals being moved from one region to another, according to Catherine McLoughlin, policy adviser on animal health and welfare at the National Farmers' Union. And because the disease is no threat to humans, any culling that was required would not receive compensation.
"There's no slack in the system, so it could prove disastrous for some farmers," she said. "Movement restrictions in the south east and south west could prevent store animals getting to finishers and finished cattle getting to abattoirs in other regions.
"The disruption to trade would be pretty horrible for our farmers and could have welfare implications for animals unable to get to pasture."
NFU chief livestock advisor Peter King appealed for retailers to stand by British lamb and beef in the event of an outbreak. "They must not use it as an excuse to source product from
There are no implications for human health because infected sheepmeat doesn't enter the food chain, even though it looks and tastes the same as usual.
But in southern Europe where the virus is quite common, it can decimate sheep herds in weeks. Cattle also carry the disease, which is spread by infected midges, but they usually don't show symptoms.
Last year the disease got as far as Ostend in Belgium - just a short waft across the Channel from Kent for a midge. And if the summer is another hotter than average one, scientists say blue tongue could arrive and spread in the UK fairly easily.
Defra said it would come down hard on any outbreaks of the disease in an effort to prevent it spreading. It did not plan to resort to a mass cull, as in previous outbreaks, however.