In the 1960s, the BBC set out to investigate local reports of secret, shocking World War Two experiments, dangerous contamination and unexplained animal deaths on a remote island off the coast of Scotland.

"Hereabouts, they call it the island of death, the mystery Island, and for good reason," said windswept BBC reporter Fyfe Robertson as he stood across the sea from the remote and desolate Scottish island of Gruinard in 1962.

"Now, this is not a story of old dark deeds or Highland superstition. No, this story started in 1942. The war had been going on for three years when suddenly a group of scientific boffins from the War Office took over the island and started experiments so secret that even today, 20 years later, very few people know what went on over there. The local people were told nothing."

Robertson was aiming to investigate the stories of dangerous government experiments that were believed to have happened on Gruinard. At the time he was reporting, the UK's Ministry of Defence had already declared the island off-limits and Robertson couldn't persuade fearful locals to sail him around the island to get a closer look at it.

It was an environmental catastrophe. Shockingly, the island remained dangerously contaminated and a no-go area for nearly half a century, until, on this day in 1990, the UK government finally declared Gruinard Island safe.

The truth was that Gruinard Island had been the site of a clandestine attempt by the UK during World War Two to weaponise Anthrax, a deadly bacterial infection. The exact details of what had happened there would only come to light when in 1997 the government declassified a film that the military had shot at the time, which detailed the experiments.

The project, called Operation Vegetarian, had started under Paul Fildes, then head of the biology department at Porton Down, a military facility in Wiltshire, England, that still exists today.

Porton Down had first been established in 1916 as the War Department Experimental Station to study the effects of chemical weapon agents, which were increasingly being used as World War One progressed. In the 1940s, with Britain at war again, Porton Down was charged with developing biological weapons that could be used against Nazi Germany to catastrophic effect, minimising actual direct combat between troops.

The plan was to........

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