Gruinard: The Anthrax Test Island and a Secret That Lasted 48 Years

In 1942, while Britain was preparing for a war for national survival against Nazi Germany, Porton Down scientists brought sheep to Gruinard Island off Scotland’s northwest coast. The island had been bought by the military, closed, and given the code name X Base. The goal was not to study a natural outbreak. They wanted to know what an anthrax-spore weapon could do in the field.

The tests were filmed in a military record. Sheep were kept in separate areas, an anthrax-filled bomb was activated nearby, and blood and tissue were examined afterward. Animals that inhaled the cloud began dying within days. The island and equipment became contaminated. The 1956 film still carried a reminder that it had been secret.