Gruinard Island - Biological Warfare Testing

Biological Warfare Testing

Gruinard was the site of a biological warfare test by British military scientists from Porton Down in 1942, during the Second World War. At that time there was an investigation by the British government into the feasibility of an attack using anthrax: to test the vulnerability of Britain against a German attack and the viability of attacking Germany with a British bio-weapon. Given the nature of the weapon which was being developed, it was recognised that tests would cause widespread and long-lasting contamination of the immediate area by anthrax spores. In order to limit contamination a remote and uninhabited island was required. Gruinard was surveyed, deemed suitable and requisitioned from its owners by the British Government.

The anthrax strain chosen for the Gruinard bioweapons trials was a highly virulent type called "Vollum 14578", named after R. L. Vollum, Professor of Bacteriology at the University of Oxford, who supplied it. Eighty sheep were taken to the island and bombs filled with anthrax spores were exploded close to where selected groups were tethered. The sheep became infected with anthrax and began to die within days of exposure. Some of the experiments were recorded on 16 mm colour movie film, which was declassified in 1997. One sequence shows the detonation of an anthrax bomb fixed at the end of a tall pole supported with guy ropes. When the bomb is detonated a brownish aerosol cloud drifts away towards the target animals. A later sequence shows anthrax-infected sheep carcasses being burned in incinerators following the conclusion of the experiment.

Scientists concluded after the tests were completed that a large release of anthrax spores would thoroughly pollute German cities, rendering them uninhabitable for decades afterwards. These conclusions were supported by the discovery that initial efforts to decontaminate the island after the biological warfare trials had ended failed due to the high durability of anthrax spores.

In 1945 when the owner sought the return of Gruinard Island, the Ministry of Supply recognized that the island was contaminated as a result of the wartime experiments and consequently it could not be derequisitioned until it was deemed safe. In 1946, the State agreed to acquire the island and to take on the onus of responsibility. The owner or her heirs and beneficiaries would be able to repurchase the island for the sale price of £500 when it was declared "Fit for habitation by man and beast".

For many years it was judged too hazardous and expensive to decontaminate the island sufficiently to allow public access. Gruinard Island was quarantined indefinitely as a result. Visits to the island were prohibited, except periodic checks by Porton Down personnel to determine the level of contamination.