Bird flu has been discovered at a farm near Dereham, Norfolk.

Preliminary tests carried out on a number of dead chickens at the farm found that they tested positive for the virus.

However, the strain is thought to be the H7 strain of the virus, which is not as virulent as the H5N1 strain which a dead swan found earlier this month in Cellardyke, near Fife, Scotland, tested positive for.

As many as 35,000 chickens at the farm have been slaughtered as a precaution and further tests are being carried out to determine the strain of the virus.

A spokesman for Defra said: “Restrictions have been placed on the farm and birds on the premises will be slaughtered on suspicion of an avian notifiable disease.”

He added: “When the additional laboratory tests are known, further action may be taken.”