Vets have been ordered to slaughter 25,000 chickens after an outbreak of bird flu was confirmed in Oxfordshire.

The outbreak - the first in the county - was discovered at Eastwood Farm between Shenington and Shutford, about 10 miles west of Banbury.

The farmer contacted the Department for Food and Rural Affairs yesterday after noticing his birds were showing suspicious symptoms.

Nigel Gibbens, the Government's chief veterinary officer, tonight confirmed the chickens had tested positive for the H7 strain of Avian Influenza - one of two strains which can be highly contagious - but not the deadly H5N1 strain.

He said the virus did not transmit easily to humans and almost all human H7 infections so far had been associated with close contact with dead or dying poultry.

A control zone has been put in place.

A neighbouring farmer, who did not wish to be named, said: "I am just terribly sad for the farmer. Luckily I don't have poultry here but I feel very sad - they are good people who work hard."

Another farmer added: "I am surprised, because there haven't been cases of bird flu for a while.

"These things are generally spread by wild birds, I presume that is what has happened here."

Police cordoned off part of Epwell Road, while Defra officials set up a temporary control area in which all birds must be kept inside.

The department is urgently considering whether any wider measures were needed.

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

Oxfordshire County Council's chief emergency planning officer John Kelly said the issue was being dealt with by the county's trading standards department.

He added: "It is not an emergency planning matter - I would certainly say to people they should not worry."

Linda Ayres, owner of Hangland Farm Ostriches in nearby Upper Wardington, said: "My birds are out to grass right now. We will certainly have to look at getting them in.

"Before there has certainly been nothing close enough to us to worry us. It will be the first time we have had it to worry about."

Dr Judith Hilton, head of microbiological safety for the Food Standards Agency, said: "This case of bird flu poses no safety implications for the human food chain."