The current Prevention Zone means that poultry across the country, even small backyard flocks, must be kept inside or separate from wild birds until 28 February. The rest of the UK and other countries have similar outdoor bans.

However, based on the latest situation and current scientific advice from the Chief Veterinary Officer, from 28 February the government anticipates adopting a more targeted approach, although the decision is not yet final. This would involve mandatory biosecurity measures across the country and continued housing or netting over birds' ranges in higher risk areas. These measures would be reviewed at the end of April.

These measures would save free range labelling for many producers. As the housing order lasts 12 weeks up to 28 February, any extension to the outdoor ban would mean no poultry products in the country could be labelled free range under EU law. Various countries have been trying to get an extension to the 12 week 'derogation' period, but these measures avoid relying on regulators in the EU to maintain free range.

Chief Veterinary Officer Nigel Gibbens said: "Effective disease control will always be our priority. Based on the current situation, we believe mandatory biosecurity across England, combined with targeted housing or range netting in higher risk areas, is the best option to control disease, protect birds’ welfare and ensure consumers can buy free range products.

"H5N8 continues to circulate in wild birds and poultry keepers must remain vigilant. This proposal does not mean a return to business as usual and we will continue to do everything we can to reduce the risk from this disease."

Although poultry will be allowed outside, birds must still be kept separate from wild birds, so the government said the outdoor access should be dependent on meeting certain strict biosecurity criteria.

Poultry keepers with more than 1,000 birds will have to meet additional biosecurity measures including identifying clearly defined areas where access is limited and vehicles, equipment and footwear must be disinfected.

While the risk of H5N8 remains high across the country, areas close to substantial inland or coastal bodies of water, where significant numbers of wild birds collect, are at an even higher risk. In these areas, the risk is considered too great to move to the alternative biosecurity package and compulsory housing or total netting will continue to be mandatory. Those producers who use netting to cover the ranges rather than using housing will be allowed to market eggs as free range.