The ring rot was identified during a Defra inspection

The discovery of the devastating potato disease was confirmed on John Morgan's farm in Bwlch in the Brecon Beacons, during an annual survey by Defra in November.

Mr Morgan, who could face losses of up to �400,000, has been told that no compensation will be available to him from the Welsh Assembly Government.

A month after the outbreak on Middlewood Farm the potato business is yet to re-start.

Mr Morgan said he knows taking legal action could be a long drawn out process.

"We've got to try and keep cool as it's not going to happen in five minutes," he said.

"The biggest problem is surviving in the meantime because you're expecting to be able to sell this crop.

"There's so much monetary pressure," he added.

'Massive blow'

Although ring rot poses no risk to human health, farmers leaders in Wales said the news was a "massive blow" to the industry and has been branded the potato equivalent of foot-and-mouth.

Annual losses to US potato farmers caused by ring rot have been as high as 50%.

Farmers are also worried about the effect on the seed market if the UK loses its disease-free status.

The UK's first outbreak of ring rot was found at Middlewood Farm

So far tests on 80,000 samples at Middlewood farm have shown that only one batch of imported potatoes is contaminated.

A total of 20 tons of potatoes imported from Holland will have to be destroyed but officials still have to decide what to do with the rest.

Transporting the potatoes off the farm for destruction could cost �25,000.

Disinfection of the farm buildings and machinery would cost much more.

With no compensation on offer and warnings that the farm could be out of business for four years, Mr Morgan has begun a legal battle over who is to blame.

Potato ring rot is a disease which is widespread in crops across Europe, having been identified in recent years in France, the Netherlands and Denmark.