THE island looks harmless enough. A sudden slash of sunshine through the clouds lights up the heather, and a visitor looking on might think it a pleasant place to live.
But Gruinard is uninhabited and likely to remain so for some time to come, on account of its frightening past.
Talk about biological warfare and the possible use of anthrax has centred round the dreaded prospect of an attack on London. But Gruinard, just half a mile off the Wester Ross coast, was once Base X, 520 acres of land used to experiment with chemical death.
Yesterday, tourists on the beach at Little Gruinard, half-way between Ullapool and Gairloch, knew nothing of the island that could be seen lurking through a gap in a promontory.
Liam Young, one of a group of environmental students from Edinburgh University, said: "I was never aware of that. If I was living here, it would bother me."
Sean White, a Gloucestershire holidaymaker, walking with his girlfriend, Charlotte, under the gaze of the moody-looking mountains, said: "I have come up here a few times but had never heard of it."
But Kenneth Mackenzie, a retired sheep farmer born within sight of the island, had certainly heard of it. "It still bothers me. There has been an awful lot of illness in the area - brain tumours and cancer. For a remote area, the death rate is very high," he said.
Gruinard was chosen by the wartime government in 1941 to test the effect of anthrax spores on sheep. Nazi Germany was thought to be considering biological warfare, and the British line was that an antidote was needed.
The tethered sheep on Gruinard duly died. Later, 63 animals (50 sheep, seven cattle, two horses, three cats and a dog) on the mainland were also infected when a carcase from Gruinard washed ashore after a botched attempt to bury the sheep in a cave.
Today, scientists reckon 100kg of anthrax released over a large city on a clear night could kill up to three million people.
Although the War Cabinet concluded it could not bring itself to initiate "these forms of frightfulness", documents later revealed plans to mass-poison German cattle in the bizarrely named Operation Vegetarian.
The island was declared a no-go area for nearly 50 years and, even now, few would dream of considering it for a day out or even a five-minute stopover.
Recently, it emerged that, despite assurances of safety, the government had set aside a contingency fund to compensate anyone proving the hard way that it was still unsafe.
Mr Mackenzie, who was a boy at the time of the tests, recalled: "Whenever they did anything they chose a calm day and they put up a smoke screen using a boat that circled the island. People didn’t have a clue what was going on.
"I don’t know why they picked Gruinard. The war lords just looked at a map of the north-west and thought: this will do."
Mr Mackenzie’s father would never let him land on the island, but he paid one brief visit five years ago.
"If you get up first thing in the morning and see the sun shining on it, it is a beautiful island. You can see the runrigs on the east side. I remember the last man who lived on the island. I think John Cameron was the name.
"Before the war, the grazing was good and rabbits were controlled. Now, it’s overrun with rabbits and rats."
Roy Macintyre, the councillor for the area, said it was long after the war before the local population discovered the experiments had been going on.
"It was to some extent dragged out of the authorities. There was a lot of suspicion because there had been curious activities on the island.
"Animals washed ashore were quickly taken for examination by government veterinary scientists. That’s the way things were done then. It couldn’t happen now."
The government, which had leased the island, bought it in 1947 for 500 and, many years later, sold it back for the same amount to the Eilean Darach estate.
The island was declared safe in 1990 and, in 1994, John Robinson, a crofter originally from London, grazed sheep on the once poisoned acres.
At one point, planning permission was obtained to build a house. But none was ever built. No sheep graze the island, now owned by another local estate.
I ask Mr Mackenzie if he would ever live on the island. He says: "Would you?" I shake my head. He shakes his too.