Chickens on a farm in Oxfordshire have tested positive for the H7 strain of bird flu, the Department for Environment, Food and Rural Affairs said this evening.

All birds on the infected farm near Banbury will be slaughtered as a precautionary measure, after the case of avian flu was confirmed by the new chief veterinary officer, Nigel Gibbens.

The Health Protection Agency said the H7 strain of avian flu was largely a disease of birds and did not transmit easily to humans. Despite this, Defra said testing was continuing to discover whether the strain of bird flu was a highly pathogenic one.

In the meantime, a temporary control zone with a 3km inner zone and a 10km outer zone has been established around the infected premises.

In the inner zone, poultry must be housed and kept isolated from wild birds, and across the whole zone, movement of birds and bird gatherings are banned.

Mr Gibbens said: "I would stress the need for poultry keepers to be extremely vigilant, practise the highest levels of biosecurity and report any suspicions of disease to their local animal health office immediately."

The Food Standards Agency said the case of bird flu "poses no safety implications for the human food chain".

Dr Judith Hilton, the FSA's head of microbiological safety, said: "Properly-cooked poultry and poultry products are safe to eat. The science shows that the virus isn't contracted by eating food, but usually by close contact with infected birds."

Although H7 bird flu has on occasion infected humans, it is far less virulent than the H5 virus that has killed more than 240 people worldwide in the past five years.