Revealed: MoD cover-up on Gruinard anthrax contamination

The Ministry of Defence (MoD) covered up evidence that toxic contamination could have spread from Gruinard island to the mainland in north west Scotland, according to government documents seen by The Ferret.

After a direct action protest dumping soil laced with the deadly toxin, anthrax, in 1981, MoD officials privately admitted that it could have come from two headlands across the sea from the island. If this was revealed, it would be “potentially embarrassing”, said one.

They cautioned that the “sleeping dog” of mainland contamination should not be disturbed. If publicly questioned “we should not mention the existence of any particular form of data”, suggested one senior official in a confidential letter in May 1982. 

At the time the MoD denied that the mainland could have been contaminated by secret wartime experiments on Gruinard, exposing sheep to anthrax and killing them. Now it says the island has been “deemed safe”, but hasn’t commented on mainland contamination.

The Scottish National Party described the revelations as “extremely alarming” and demanded an environmental audit of the MoD’s use of Scotland as a “dumping ground”. Campaigners accused the MoD of misleading the public about a potential health risk.

Revealed: MoD cover-up on Gruinard anthrax contamination 2
An actor looking at Gruinard island (photo thanks to BBC Scotland/Indelible Telly)

Gruinard in Wester Ross was used by Churchill’s wartime government in 1942 and 1943 as a biological weapon testing ground. Bombs packed with a deadly form of anthrax were exploded upwind of 80 tethered sheep, killing them all.

The island remained contaminated and closed to visitors for more than four decades. In 1981 an anonymous protest group mounted “Operation Dark Harvest” and dumped containers of soil by the MoD’s then Chemical Defence Establishment at Porton Down, in Wiltshire, and in Blackpool during the governing Conservative Party’s annual conference.

The protestors initially said the soil was from Gruinard but then later suggested it had come from the mainland near the island. Government scientists detected anthrax in the soil dumped at Porton Down but not in the soil left in Blackpool.

In 1986 the MoD carried out a major clean-up operation on Gruinard by removing contaminated topsoil and spraying the island with formaldehyde. In 1990 the UK Government declared Gruinard safe, and allowed visitors for the first time in 48 years.

Now MoD documents revealing that the mainland could also have been contaminated in the 1940s have been unearthed from the National Archives at Kew in London for a BBC Scotland television documentary, to be broadcast on 1 March 2022. The documents have been shared with The Ferret.

They show that the Dark Harvest claims prompted the MoD to review evidence that the mainland could have been contaminated. The outcome was reported in a confidential memo from Rex Watson, then head of the Chemical Defence Establishment at Porton Down, on 22 December 1981.

“Since on at least one occasion a test was performed when the surface wind direction was at the limit of safety, it is possible that one or more clouds of the anthrax aerosol passed over the mainland coast,” he wrote.

Watson identified Static Point and Rubha Beag as two headlands near Gruinard that could have been contaminated. The precautions taken in 1942-43 did not “absolutely guarantee that there could be no contamination of either adjacent headland,” he said.

“Although I very much doubt if anyone could be found to claim that this level of possible contamination would constitute a hazard of any significance, it would clearly be potentially embarrassing to the department to renew our argument with Dark Harvest if a more searching review of our data were to follow.”

I do not believe it would be sensible to disturb the sleeping dog of whether there is any anthrax contamination on either of the two headlands.

Dr M H C Warner, Ministry of Defence

On 10 May 1982 a senior MoD official, Dr M H C Warner, wrote to Watson discussing “the public line to be taken” on mainland contamination from Gruinard. “I would suggest that while we could say we are cooperating with the Scottish authorities in their investigations, we should not mention the existence of any particular form of data,” he said.

In a later memo on 18 May 1982 Warner apologised if his “scrupulous concern for honesty” had created “unnecessary concern”. 

He added: “I do not believe it would be sensible to disturb the sleeping dog of whether there is any anthrax contamination on either of the two headlands downwind of Gruinard Island. 

“It would be extraordinarily expensive to sample and measure the area that could have been affected. We would be very lucky (and miserable) if a random test were to come up positive.”

As far as is known, the MoD did not test the mainland by Gruinard for anthrax contamination. In 1982 one senior official highlighted the possibility that the owners of contaminated land on the mainland could “mount a claim for compensation”.

The MoD appears to have covered up evidence of anthrax contamination on the Scottish mainland from Gruinard island.

Deidre Brock MP, SNP environment spokesperson

The SNP’s environment spokesperson at Westminster, Deidre Brock MP, described the revelations as “extremely alarming”. She called for a “full environmental audit” of the MoD’s “messes” in Scotland.

“The MoD appears to have covered up evidence of anthrax contamination on the Scottish mainland from Gruinard island in the 1980s,” she told The Ferret.

“It isn’t the first time the MoD has shown shocking disregard for public health and the environment. It has been using Scotland’s islands and coasts as a dumping ground.”

The Scottish Green MSP for the Highlands and Islands, Ariane Burgess, demanded openness. “Gruinard island is a reminder of the toxic legacy of the Ministry of Defence’s use of the highlands and islands as a playground for its dark war games,” she said.

“It is bad enough that a Scottish island was used to test vile chemical weapons in the first place. But if, as it seems, subsequent contamination has spread and then been covered up, people deserve to know.”

The land campaigner and former Green MSP, Andy Wightman, warned that the MoD could have misled the public and put the health of local residents at risk. “The MoD must now come clean about the concerns raised in these documents and clarify what hazards may still exist,” he said.


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The Scottish Campaign for Nuclear Disarmament argued that “inhumane and indiscriminate” weapons posed “unheralded risks” to the countries that develop them. “With no mechanisms for rigorous public scrutiny, complacency about risk and duplicitous silences about accidents are likely,” said campaign chair, Lynn Jamieson.

The Scottish Government said that it did not hold any records on Gruinard contamination, and referred queries to the MoD.

The Ministry of Defence did not respond to questions about anthrax contamination on the mainland. “Gruinard Island was decontaminated and deemed safe in 1987,” said an MoD spokesperson.

“As part of the sale of the island in 1990, the MoD agreed to undertake further work, if necessary, within 150 years of its sale.”

Documents about Gruinard from the National Archives

Source documents mentioned in this story are available to Ferret members as a download by clicking the button below.

The Ferret has published thousands of source documents and datasets since we were founded in 2015. You can search them here:

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The Mystery of Anthrax Island by Indelible Telly is due to be broadcast on BBC Scotland at 10pm on Tuesday 1 March. Images thanks to BBC Scotland/Indelible Telly.

This story was published in tandem with iNews.

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