Gruinard Island Gruinard Island ( ; ) is a small , oval - shaped Scottish island approximately long by wide , located in Gruinard Bay , about halfway between Gairloch and Ullapool . At its closest point to the mainland it is just over offshore . The island was made dangerous for all mammals by experiments with the anthrax bacterium , until it was decontaminated in the late 20th century . Early history . The island was mentioned by Dean Munro who travelled the area in the mid 16th century . He wrote that it was Clan MacKenzie territory , was " full of woods " , ( a striking comparison with its treelessness today ) and that it was " guid for fostering of thieves and rebellis " . The population was recorded as six in 1881 , but Gruinard has been uninhabited since the 1920s . 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 rope s . 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 Crown 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 . Operation Dark Harvest . In 1981 newspapers began receiving messages with the heading " Operation Dark Harvest " which demanded that the government decontaminate the island , and reported that a " " team of microbiologists from two universities " " had landed on the island with the aid of local people and collected of soil . The group threatened to leave samples of the soil " " at appropriate points that will ensure the rapid loss of indifference of the government and the equally rapid education of the general public " " . The same day a sealed package of soil was left outside the military research facility at Porton Down ; tests revealed that it contained anthrax bacilli . A few days later another sealed package of soil was left in Blackpool , where the ruling Conservative Party was holding its annual conference . The soil did not contain anthrax , but officials said that the soil was similar to that found on the island . Decontamination . Starting in 1986 a determined effort was made to decontaminate the island , with 280 tonnes of formaldehyde solution diluted in seawater being sprayed over all 196 hectares of the island and the worst - contaminated topsoil around the dispersal site being removed . A flock of sheep was then placed on the island and remained healthy . On 24 April 1990 , after 48 years of quarantine and 4 years after the solution being applied , junior defence minister Michael Neubert visited the island and announced its safety by removing the warning signs . On 1 May 1990 , the island was repurchased by the heirs of the original owner for the original sale price of £500 . As of October 2007 there have been no cases of anthrax in the island flock . Popular culture references . The island is mentioned in the novels " The Enemy " by Desmond Bagley ( 1977 ) , " Sea of Death " by Richard P . Henrick ( 1992 ) , " The Fist of God " by Frederick Forsyth ( 1994 ) , " Quantico " by Greg Bear ( 2005 ) , " The Big Over Easy " by Jasper Fforde ( 2005 ) , " Forbidden Island " by Malcolm Rose ( 2009 ) , " And then you die " by Iris Johansen ( 1998 ) , " The Island " by R J Price ( better - known as the poet Richard Price ) ( 2010 ) and " The Impossible Dead " by Ian Rankin ( 2011 ) . In issues 187 – 188 of the comic book " Hellblazer " , in a story titled " Bred in the Bone " , the protagonist ' s niece finds herself on Gruinard surrounded by flesh - eating children . The issues were released in 2003 and were written by Mike Carey and illustrated by Doug Alexander Gregory . An episode of the British wartime TV series " Foyle ' s War " entitled " Bad Blood " involved biological testing – a strong reference to the Gruinard testing . The " Hawaii Five - O " episode " Three Dead Cows at Makapu , Part 2 " featured a scientist played by Ed Flanders who threatened to unleash a deadly virus on the island of Oahu . When being interrogated , the scientist briefly mentions Gruinard Island and how it will be uninhabitable for a century due to anthrax experiments . Outlying Islands , a Fringe First winning play by Scottish dramatist David Greig , is a fictionalised account of two British scientists ' visit to an island in Scotland where the government plans to test anthrax inspired by the story of Gruinard .