A third case of foot-and-mouth disease in three days in a region that was virus-free for months yesterday fuelled fears that other farms there could be infected.
"Draconian" new controls were imposed on a 400 square mile area in Northumberland after the case was confirmed in an attempt to stop the virus from spreading.
The move came amid fears that it could already be too late and other farms in the county could be infected.
A UK Farmers' Union north- east director, Mr Richard Ellison, said: "We fear there are going to be more, it's showing that sort of pattern. It is not looking good. They have suspicions it has already reached other farms."
Mr Ellison said it was still not known how the virus spread to the three farms, all within about five miles of each other and close to the town of Hexham.
An investigation is continuing into how many other farms could be facing culls as "dangerous or contiguous" contacts.
The fresh cases were a double blow to the community, where the original case of the disease was confirmed in February, as animal movement restrictions in the area had been expected to be lifted within weeks. Instead, tougher restrictions known as "Blue Box" measures have come into force across the 400 square mile zone.
The regulations include the withdrawal of all licences for animal movement and stringent bio-security being enforced at farms, including disinfectant foot baths and sprays. All footpaths in the area have been closed.