An isolated case of anthrax disease in a cow was confirmed at a farm in Wiltshire following the death of the cow.
Movement restrictions were imposed at the farm and the animal’s carcass was incinerated. No other animals have been affected.
The previous outbreak in livestock in Great Britain was in 2006.
Public Health England said the risk of infection to humans was "very low" following the discovery.
Protesters opposed to a planned development at Up Mudford in Somerset have gathered in the local cemetery.
Members of Friends of Mudford Action Group are against proposals for 765 houses, a school, and care home on a site they believe to be at risk of harbouring deadly anthrax spores.