FARMERS in the region last night reacted with horror at the prospect of a total ban on selling British lamb if BSE is found in the nation's sheep.

The drastic move is one possibility being considered by the Ministry of Agriculture, Fisheries and Food (Maff) in the event of a confirmed outbreak of the disease in the national flock.

Another is that only meat from sheep genetically immune to diseases such as BSE would be allowed into butchers and supermarkets.

These contingency plans emerged as a Food Standards Agency working party recommended urgent action to deal with the possibility of BSE infecting sheep.

A Maff spokeswoman stressed that although both possibilities were being considered, no final decisions had been taken yet.

The region's sheep farms outnumber cattle farms by as much as two-to-one and thousands of farmers would be affected in the North-East and North Yorkshire.

Mike Wilkin, a sheep and arable farmer from Dalton-on-Tees, said: "It would be a total disaster if lamb was removed from sale."

County Durham sheep farmer Michael Wise added: "This must be the most extreme reaction they can think of."

And Richard Betton, former County Durham National Farmers' Union chairman and the union's hill farming delegate to London, said: "It would be the end of hill farming in the North of England - the majority of farmers keep sheep."

He added that for every person in agriculture, there were 15 more whose livelihood was linked to the industry.

The Food Standards Agency warned that BSE in sheep could be "masked" by a similar disease, scrapie, which has affected flocks for more than 200 years but has never proved harmful to people.

BSE, on the other hand, is believed to have caused variant CJD in humans, claiming more than 80 lives.

An NFU spokesman said farmers would have to face up to the "terrifying" prospect of entire flocks being destroyed if BSE was discovered in sheep.

"The NFU would be letting sheep farmers down, and farmers would be letting themselves down, if they did not contemplate this worst-case outcome," he said.

FSA chairman Sir John Krebs said whether or not sheep were contracting BSE was an unanswered question.

"We simply do not know," he said. "Of the 40 million sheep in Britain, some 4,000 do succumb annually to scrapie, which appears not to have any human health risk.

"It is possible, however, that some of these animals are actually suffering from BSE."

He said a new method of rapid screening using biochemical markers was needed. This could be used either to test all sheep diagnosed with scrapie, or for the random testing of all slaughtered sheep.

The Ministry of Agriculture has launched a plan to breed scrapie and any related diseases such as BSE out of sheep using genetically resistant rams. But the FSA said this would take ten years or more.

The NFU stressed that no trace of naturally occurring BSE had ever been found in sheep. But the spokesman agreed that "draconian" measures would have to be taken if the national flock turned out to be infected.

When the BSE epidemic broke out, the total destruction of all Britain's cattle was seriously considered, but the realisation that it was not necessary stopped this.

However, in sheep experimentally infected with BSE, the infectious agent is not "neatly trapped" in certain organs, as it is in cattle.

The report also called for a complete ban on farm feeding practices that turn animals into cannibals. In reality, this would mean extending the current ban on feeding recycled meat and bone meal to livestock so that it included blood, gelatin and tallow.

Mike Attenborough, of the Meat and Livestock Commission, said there was no reason to worry about eating British lamb. He took issue with the FSA's claim that only 200 sheep were being screened for BSE, insisting that more than 3,000 had been tested