Disease statistics

Cases so far: 1,998 Animals slaughtered: 3,802,000 Awaiting slaughter: 19,000

According to the Department of Farming and Rural Affairs (Defra), it is the first case in County Durham since 3 June.

The farm was on the south-west tip of the "blue box" exclusion zone, designed to contain the virus, which has now been extended 3km eastwards.

It is the second time it has been extended in two days - the original 220 square mile box around the Allendale area was boosted by 100 square miles to the north on Saturday.

This followed a confirmed case at Greyside Farm at Newbrough, near Hexham, which was outside the zone.

Burial site re-opened

The government also announced on Sunday that it would reopen County Durham's Tow Law burial site, used in the worst days of the crisis.

Seventy soldiers are helping co-ordinate the cull

A spokesman said it was a decision taken "reluctantly", because local rendering sites can no longer cope with the numbers of animals being culled.

Local residents had previously managed to get the site temporarily closed after demonstrating against a steady convoy of vehicles carrying carcasses in front of their homes.

Disease 'unnoticed'

And on Sunday Defra minister Lord Whitty said the disease had probably been lying unnoticed in Northumberland for "some time" before it was detected 10 days ago.

He said original theories that the latest outbreak had been brought into the area were growing less and less likely as the outbreak developed.

He said: "Rather more seriously, and increasingly likely, it looks as if the disease had been there for some time before it was detected.

"That is why we are picking up cases outside the original area now and why it is absolutely vital that we do contain the disease."

Arthur Griffiths, divisional veterinary manager, said of Sunday's case: "This is more disappointing news for everyone in the area and, in particular, for the farming industry.

"My colleagues are working around the clock to do their best to eradicate this disease.

"We cannot stress enough how important it is for everybody concerned to carry out strict biosecurity on their own footwear as well as their vehicles.

"We want to thank everyone for their co-operation so far at the cleaning and disinfectant points in the 'blue box'."

46,000 animals

On Sunday more soldiers arrived in Northumberland to help government officials, farmers and vets co-ordinate the slaughter and disposal of infected livestock.

Culling has been taking place on 62 "dangerous contact" sites identified in the area.

More than 46,000 animals have been slaughtered or are awaiting slaughter in the latest outbreak.

A further two cases were also confirmed at farms in Cumbria on Sunday, bringing the nationwide total of outbreaks to 1,998 since the disease first struck in February.