Government veterinarians have confirmed that it is the H5N1 strain of bird flu that has affected the flock - the same strain of the virus found across Asia, identical to the strain found in outbreaks in Czech Republic and southern Germany in recent weeks.

All 6,500 birds - 5,000 turkeys, 1,000 ducks, 500 geese - at the infected farm were immediately culled. Additionally, a 3km protection zone and a 10km surveillance zone has been set up. Poultry on another two farms feared to have been in contact with the infected farm may be culled in the next few days.

Farmers in UK suspect that it is the migratory birds that may be the cause of this latest outbreak. Defra's inquiries into the source of the virus are focusing on wild bird transmission but the exact source is still being investigated.

The arrival of the deadly H5N1 strain of avian influenza virus comes at the worst time for the poultry industry as it prepares for Christmas.

Government veterinarians fear that the H5N1 strain might be endemic in the British wild bird population.

East Anglia produces about a third of Britain’s turkeys and there are fears that if the virus takes hold the £400 million (€567 million) market for Christmas birds will be lost. There are three million birds alone in the 10km surveillance zone around the infected Redgrave Park Farm.

There is particular concern that the infected free-range turkeys had been allowed to mingle with wild birds that gather at an ornamental lake which is part of the infected farm premises, and that a reservoir of virus may have built up in the bird population on the farm.