MORE troops were called up in the North-East last night as the Army struggled to hold the line against foot-and-mouth disease.

Brigadier Andrew Farquhar - the officer heading the military operation in the region - said that about 120 soldiers were now helping Ministry of Agriculture (Maff) vets.

The Army's role was stepped up as more cases were confirmed in the region and the national total reached 728.

It has set up an operations centre at government buildings in Kenton Bar, Newcastle, to co-ordinate the response in the region.

Brig Farquhar said his men were working alongside 120 vets with plans to take on more animal experts.

North Yorkshire's sixth case was confirmed yesterday, resulting in a new infected area centred on Bellerby, Leyburn.

Maff vets found infected cattle at South View Farm in the village and the slaughter of the entire herd will begin this morning.

The discovery came only 24 hours after the disease was confirmed at Park Hill Farm, Danby Wiske, near Northallerton, where the cattle have now been slaughtered. The livestock at four adjoining farms, which includes three pedigree dairy herds, are expected to be killed today as a precautionary measure.

In a drastic bid to prevent any further spread, 1,000 sheep in the county are also being destroyed.

About 200 have already been killed at Langton, near Malton, and a further 800 are being slaughtered at Husthwaite, near Easingwold.

The sheep were regarded as high risk because of their contact with Longtown Market in Cumbria, a hotbed of the disease.

The sheep are being taken to the giant burial pits at Great Orton, near Carlisle, for disposal but the Danby Wiske animals are expected to be burnt on the farm today.

At Leyburn, it is likely that the slaughtered animals will be disposed of on Ministry of Defence land, although it has still to be decided whether it will be by burying or burning.

With four cases in Hawes confirmed earlier this month about half of North Yorkshire is now subject to movement restrictions.

In Cumbria, Army commander Brigadier Alex Birtwistle was joined yesterday by Defence Secretary Geoff Hoon and General Sir Michael Jackson, Commander in Chief of Land Command for the Army, who were visiting the region to see for themselves what was happening.

They both visited the disused airfield where the disposal of carcasses and the slaughter of healthy animals is taking place.

General Jackson, responding to a question about the epidemic, replied: "This is a different conflict to a war. It is a tragic disease in our own country. I hope we can win."

Meanwhile, Prime Minister Tony Blair admitted to MPs that he did not know how long the outbreak would last.

He revealed that there were well over a million movements of sheep in the critical weeks before the disease was detected as he spelt out the huge scale of the challenge to control and eradicate it.

Shortly before Brussels gave Britain the go-ahead for a limited vaccination programme - if the Government chooses to take up that option - Mr Blair used Prime Minister's Questions to deliver a bleak assessment of the scale of the problem facing the Government.

Later, Brussels gave Britain the go-ahead to vaccinate 180,000 cattle in Cumbria and Devon.

Agreement "in principle" for a clearly defined and limited vaccination programme came at talks between EU veterinary experts meeting in Brussels - but it is still up to the UK Government to decide if it wants to take the vaccination route.

In an attempt to persuade sceptical farmers of the arguments for vaccination - a programme is likely to require emergency legislation - ministers held a series of discussions with National Farmers' Union president Ben Gill.