Three new Bluetongue cases were found in Sussex, Essex and Norfolk

The Department for the Environment, Food and Rural Affairs said the case was found near Poole, in Dorset. The zone covers Dorset and the New Forest.

Three new cases have also been found in Sussex, Essex and Norfolk. Protection zones there have been extended.

The virus is spread by a species of midge and can be fatal to animals such as sheep and cows.

The discovery of three new cases means the separate protection zones covering East Anglia and parts of north west London, Buckinghamshire and Hertfordshire have been merged and extended.

Vector-free period

All the infected animals were found as a result of the testing that farmers must undertake before they are able to move their livestock out of the zones, a Defra spokeswoman said.

In risk of the virus spreading was believed to be low due to a lack of midge activity in the cold weather.

Defra said evidence suggests the animals all had the disease prior to the start of the vector-free period, making it unlikely the virus is currently circulating in the UK.

However, it is not yet clear how the disease reached the infected site near Poole.

Routine testing

Bluetongue was first confirmed in the UK in East Anglia on 28 September and other cases were in south-east England.

The latest case was identified during routine pre-movement testing.

As a result of the discovery, the wider surveillance zone which covers much of England has also been extended into south east Wales as well as all of Somerset and Devon.

A Bluetongue case was identified in Greater London last week.