Experts argue, but the crisis continues

But the findings emerge as a computer model of strategies for controlling the outbreak suggests that the government's mass slaughter policy is the most effective way of containing the disease.

Researchers said vaccinating animals in the worst-affected areas could have helped only marginally and if it was adopted in "buffer zones" could have let the disease spiral out of control.

Meanwhile, a cull of 1,300 sheep found to be carrying virus antibodies has been carried out the Brecon Beacons, sparking fears that the Welsh National Park's entire flock will be affected.

Alternative policy

The research on the economic cost of the disease was carried out by Professor Peter Midmore at the University of Wales in Aberystwyth.

He compared the likely economic impact under the current policy of culling all affected livestock with the alternative, of controlling the spread of the virus through vaccination.

Professor Midmore estimates the crisis will have cost about �5bn in total by the end of the year.

This includes the money spent on slaughter, compensation for farmers and the impact on tourism.

In contrast, he calculates that vaccinating animals in a ring around infected areas would have cut the total bill to between �1.5-2bn, even considering the likely delay in lifting an export ban on British meat and livestock.

Even now, the research suggests, vaccination around infected areas could cut the continuing costs of the epidemic by about half, unless the disease is eradicated in the next few weeks.

We have been importing meat from those countries which do vaccinate over the past few years

Organic farmer, Helen Browning

Frits Pluimers, the Chief Veterinary Officer for Holland, where they vaccinated after a foot-and-mouth outbreak earlier this year, said that once animals were immune they could be kept without risk - creating more time to manage the disease.

And organic farmer Helen Browning, who chairs the Soil Association and sits on the Meat and Livestock Commission, believes the caution surrounding vaccination is misplaced as meat from vaccinated animals is already for sale in Britain.

"We have been importing meat from those countries that do vaccinate during the past few years," she told Today.

The cull of 1,300 sheep in the Brecon Beacons will bring the total number of animals slaughtered to 6,500.

Test results on a further 4,000 are awaited, and some fear the disease now threatens the entire flock of 100,000 sheep in the Beacons.

The cycle of testing and killing is likely to continue until officials are convinced that they have got ahead of the disease.

The National Farmers' Union (Wales) wants healthy animals to be put into quarantine and later used to restock the hills.

Meanwhile, the Department of Environment and Rural Affairs (Defra) has announced the resumption of the disinfection scheme to rid farms in England and Wales of the disease.

It had been halted by the government for a two-week review amid concerns over escalating costs.

Farms were costing an average of �100,000 to disinfect - compared with an estimated �30,000 in Scotland and �10,000 elsewhere in Europe.