Bird flu control zones have been lifted around two infected Norfolk farms where 55,000 turkeys were culled in the run-up to Christmas.

Defra says all disease control activities and surveillance have now been successfully completed at North Farm in Snetterton, near Attleborough, and at a poultry farm north of East Winch, near King's Lynn - six weeks after they were confirmed as the county's first two avian influenza cases of this winter's outbreak.

Animal health officials have revoked the 3km Protection Zone and the 10km Surveillance Zone which were immediately enforced around the infected sites on December 4 and 5, which increased biosecurity requirements and restricted the movement of poultry, eggs and meat to stop the disease spreading.

Eastern Daily Press: A turkey farm at East Winch was the site of Norfolk's second confirmed bird flu case in DecemberA turkey farm at East Winch was the site of Norfolk's second confirmed bird flu case in December (Image: Stuart Anderson)

But local restrictions remain in place around another three subsequent outbreak sites in the county.

A Defra statement on the two initial cases says: "All birds on the infected premises have been humanely culled.

"Following successful completion of disease control activities and surveillance within the zone, the Surveillance Zone has now been revoked. Local movement restrictions have now been removed but the Avian Influenza Prevention Zone (AIPZ) measures remain in place."

The national AIPZ, declared in November, made it a legal requirement for all bird keepers to follow strict biosecurity measures. All poultry - including free-range and back-yard flocks - are also required to be kept indoors under a mandatory housing order later announced by chief vets in a further effort to prevent outbreaks.

The two turkey farms were the first two cases in Norfolk during this winter's devastating bird flu outbreak which later also affected two sites operated by Green Label Poultry, which supplies Suffolk-based Gressingham Foods.

One was at Homelea Farm in Great Ellingham, and the other was at Foulden Road in Ickburgh, near Watton, where around 100,000 birds were culled in a bid to prevent further outbreaks.

Protection and surveillance zones remain in place around those sites.

Gary Ford, East Anglia regional director for the National Farmers' Union, said: "We would urge all poultry keepers to remain vigilant, to maintain enhanced biosecurity and to report any signs of disease in their birds to their vet or the Animal and Plant Health Agency."

Eastern Daily Press: A 3km Protection Zone and 10km Surveillance Zone were put in place around a turkey farm near Attleborough where an outbreak of bird flu was confirmed on December 4A 3km Protection Zone and 10km Surveillance Zone were put in place around a turkey farm near Attleborough where an outbreak of bird flu was confirmed on December 4 (Image: Defra)

Eastern Daily Press: A 3km Protection Zone and 10km Surveillance Zone were put in place around a turkey farm near King's Lynn where an outbreak of bird flu was confirmed on December 5.A 3km Protection Zone and 10km Surveillance Zone were put in place around a turkey farm near King's Lynn where an outbreak of bird flu was confirmed on December 5. (Image: Defra)