Final tests are being carried out on a farm in the Bradford area to decide whether the threat of foot and mouth is finished.

Officials from the Ministry of Agriculture, Fisheries and Food (MAFF) have been taking blood samples from animals on an unnamed farm. The samples will be sent away for testing.

But farmers would not know for weeks whether the tests provided good or bad news, said a spokesman for MAFF.

Blood samples have also been taken from livestock around two farms, Bobby Green, in Queensbury, and Myrtle Grove, Clayton, as well as West Brook Farm in Rawdon.

The MAFF spokesman said: "We are still blood testing and there is one premises left to do. That could take a few days.

"We do not know when the results will be back. It depends on how many samples are sent for testing."

Even if sites around Bobby Green are given the all-clear, some will still be under restriction if they fall within the zone of Myrtle Grove.

And fears are being raised that toxins from the pyres used to destroy cattle may have seeped into the soil.

A spokesman for Friends of the Earth said toxic chemical compounds called dioxins, which are released during the burning of carcasses, can find their way into the soil, then into grazing animals and also fish.

He added they were carcinogenic and could damage the reproductive system of humans.

John Varley, farmer at Myrtle Grove, said although people might not approve of the pyres, the backlog in carcasses waiting to be disposed of meant they were necessary.

Mr Varley, whose 19 pedigree Limousin cows were culled last month as a result of foot and mouth, said: "I don't think you can only render them, with there being so many carcasses.

"But one problem with burning is what happens with the particles in the smoke when it settles. It could land anywhere and contaminate the land."