Large numbers of animals confined due to movement restrictions could 'hasten' the spread
Cattle and sheep at a farm in the village of Barbon near Kirby Lonsdale were found to be infected, officials from the Department for Environment, Food and Rural Affairs (Defra) said on Wednesday.
The last case in Cumbria, confirmed at the weekend, was on the southern edge of the area known as the Penrith Spur, a dozen miles to the north.
Ministry vets have gone to great lengths in the past fortnight to prevent the disease moving out of the spur into the Lune Valley.
Investigation
Roads have been closed to all but local traffic, and intensive disinfection carried out on those vehicles which do move.
There are more cattle and sheep than usual in the Lune valley because of movement restrictions, and it is feared this could help the disease spread rapidly.
Defra scientists say they are now trying to establish whether the case is isolated, or the start of a new larger outbreak.
The news comes just a day after government vets declared another region - the East Midlands - a "foot-and-mouth free" area.
Defra made the announcement after Leicestershire became the final county in the region to be granted "free" status.
Licence 'chaos'
Meanwhile farmers claimed on Tuesday that a new system to allow controlled movement of livestock in the wake of the foot-and-mouth crisis was in chaos.
The National Farmers' Union (NFU) said there has been complete confusion over the issuing of licences to transport animals, which was supposed to start last week.
Union officials say it is adding to the stress and hardship of farmers affected by the controls imposed to prevent the spread of the disease.
Many farmers have been unable to move their livestock since the start of the outbreak seven months ago.