The department has revealed that it is the same virus that has been moving across Eurasia and has claimed 206 lives to date, mainly in Asia.
Sixty turkeys out of a flock of 1000 died overnight on Sunday at Redgrave Park farm, near the town of Diss in Suffolk. The authorities have now culled all 5000 birds on the farm.
This is the second outbreak of the virus in poultry in the country.
The first time when the UK experienced the outbreak of H5N1 in poultry was in February this year. The virus then was thought to have come from Hungary in imported turkey meat.
Given that Redgrave Park farm has not received any deliveries that could have brought in infected poultry for four weeks, scientists are now trying to understand how the virus got there.
Getting to the source of the virus may be possible by determining its genetic sequence, as this will reveal the other viruses with which it may be related.
"The initial sequence data suggests that it's closely related to outbreaks in the Czech Republic and Germany," New Scientist magazine quoted the UK's acting chief veterinary officer, Fred Landeg, as saying.
"(This) does suggest a possible wild bird source," he added.