The results so far and the symptoms shown suggest it is a very mild strain of H5N1, less serious than other forms of the virus that have caused concern in recent years. However, further tests are being carried out to confirm precise details of the disease.

The flock is believed to be a 38,000 broiler breeder flock in Fife.

Scotland’s Chief Veterinary Officer Sheila Voas said: “All the evidence so far suggests we are dealing with a very mild form of H5N1 avian influenza, which is not the same as the strain that has been causing problems in Asia and north Africa.

"Further tests are currently being carried out to confirm this but, in the meantime, we are taking no chances.

“As a precaution to prevent the spread of disease – and in line with our robust procedures for dealing with avian flu – we have already put in place movement restrictions around the farm and all birds on the premises will be humanely culled.

"Consumers should not be concerned about eating eggs or poultry given the expert advice about food safety and human health.

“We are looking into possible sources of this infection in Scotland but it is normal for such viruses to circulate among wild bird populations, especially waterfowl.

"However, it is important that poultry keepers remain vigilant for any signs of disease and to ensure they are maintaining good biosecurity on their premises.”

Cabinet Secretary for Rural Affairs, Food and the Environment Richard Lochhead said: “We have seen a number of cases of avian influenza across Europe in the past few months, including three separate cases in England in the past year or so, but it looks like we are dealing with a very mild strain here."