"This year we are seeing the largest-ever outbreak of avian influenza in the UK," he told the House of Commons. He added that there have been 36 confirmed outbreaks so far this year.

Such outbreaks were a seasonal risk associated with migratory wild birds, he said.

Britain's Chief Vet Christine Middlemiss told BBC Radio on Thursday that around 500,000 birds had been culled as a result of the outbreaks, reported Reuters.

The highly pathogenic H5N1 bird flu was confirmed at premises in North Yorkshire and South Suffolk on Wednesday following a string of outbreaks in different locations dating back to 27 October when the strain was found at a rescue centre in Worcestershire.

All birds on infected premises were culled.

A nationwide Avian Influenza Prevention Zone was declared in England on 3 November, ordering farms and bird keepers to toughen biosecurity measures.

This was extended on 29 November to include housing measures with a legal requirement for all bird keepers across the UK to keep birds indoors.

The virus has been spreading across Europe during the last few weeks with outbreaks in several countries including France, Germany, Italy, the Netherlands and Denmark.

Britain's Food Standards Agency has said that on the basis of the current scientific evidence, bird flu poses a very low food safety risk for UK consumers, adding that properly cooked poultry and poultry products, including eggs, are safe to eat.