Tests on turkeys at two farms have confirmed the birds have a low-risk strain of bird flu called H6N1. The flu, affecting birds at Bernard Matthews' breeder farms at Yaxham, and Ubbeston, near Halesworth, was quickly ruled out as the deadly H5 or H7 strain of avian influenza.

Tests on turkeys at two farms have confirmed the birds have a low-risk strain of bird flu called H6N1.

The flu, affecting birds at Bernard Matthews' breeder farms at Yaxham, and Ubbeston, near Halesworth, was quickly ruled out as the deadly H5 or H7 strain of avian influenza. But it is thought to be the first time birds in Britain have been affected by this particular strain.

Last week, the company said tests had confirmed the birds had the H6N1 virus, one of low risk to humans. A Bernard Matthews statement said: 'This is a virus type that has been isolated in both wild birds and commercial poultry flocks in Europe over the last few years.'

A Defra spokesman said tests would be carried out to determine if the virus has high or low pathogenicity - its likelihood to spread. A statement said there was no evidence to date H6 was highly pathogenic. Results are not due for some days.

Defra started tests for bird flu on Arran Farm at Yaxham and at Ubbeston on Tuesday last week after the firm brought it to their attention. Workers had noticed an unusual drop in egg production levels.

The Health Protection Agency said staff did not have to be treated.

The two farms remain under movement restrictions.

None of Bernard Matthews Farms other operations has been affected.