The reef was dead, said the farmer. He was going to bulldoze it.

Indeed, the flat surface at the top of the reef, exposed at low tide, did lack the vibrant colours that are normally associated with the Great Barrier Reef. But did that mean it was dead? That it wouldn't matter if it was mined?

Limestone taken directly from the patch of reef would be a cheap fertilizer for the local cane farmer, but at what ecological cost to the region?

The incident that started a war

This local story was to be the seed which started a long campaign to protect the Great Barrier Reef in its totality.

It was 1967, and in Queensland the National Party government of Joh Bjelke-Petersen was about to come to power.

"It was a different sort of mindset back then, everything was there to be exploited," says local tour operator Alistair Pike.

"We had a fairly full-on development-orientated government … and mate, if they couldn't drill it, mine it, chop it down or whatever, they really didn't want to know about it.

"The move was on [to develop the reef], not just about the limestone or the lime recovery off the reef, but also there was some very serious rumblings about drilling for oil on the reef."

The government had secretly zoned up to 80 per cent of the reef for mining and lined up six mining companies to do testing.

A small public notice that appeared about bulldozing at Ellison Reef was the first time the government's plan to develop the reef came to activists' attention.

The man who read that notice was not without power, nor passion.

"He was a ratbag, a self-declared ratbag rogue, he loved calling himself 'the bastard from Bingil Bay'," says Sydney University history professor Iain McCalman.

"He was shrewd, a very shrewd, very clever guy. He knew a bit of law and was an extremely good lobbyist with great connections."

He was Mission Beach artist John Büsst (1909–1971), who worked from his home, Ninney Rise.

John Büsst stands with hand on back of chair with Zara Holt (Harold Holt's wife, who later remarried as Zara Bate). ( Supplied: Friends of Ninney Rise )

"His best buddy was Harold Holt, at that time the Liberal prime minister of Australia. They actually skin-dived together and they had a little house, the Holts, just around the corner from Bingil Bay where John Büsst was," Dr McCalman said.

"He actually went down to Canberra and button-holed Holt, and said, 'come on Harold, you've got to save this bloody reef'.

"Harold Holt said, 'look, it's a difficult situation, I've got to deal with the Queensland government. But I will promise you this, that if the Queensland government starts to mine the reef, or starts to attack the reef, I will come in and bring the federal parliament behind me.'"

Allison Büsst (John's wife), Harold Holt, an unknown man and Zara Holt pose for a photo. ( Supplied: Friends of Ninney Rise )

Soon after, Holt disappeared into the sea.

"[The activists] had to start all over again, it was one of the many setbacks that they had," Dr McCalman said.

'The closest most people will come to Eden'

Büsst was joined in the campaign to save Ellison Reef by several well-known individuals including his close friend Len Webb, a CSIRO forester, and poet Judith Wright, who was president of the Queensland Wildlife Preservation Society.

Determined to save Ellison Reef from mining, Büsst contacted then post-graduate student Eddie Hegerl from the University of Queensland to come and do a survey to determine whether the reef was, in fact, dead.

Marine researcher Eddie Hegerl is still advocating for the reef. ( ABC News: Kathy McLeish )

"We were taken out in two little tiny homemade boats that were unsafe at any speed I think, and we stayed in those boats on the reef for five days and surveyed the reef," Mr Hegerl said.

"We found that it was a perfectly normal coral reef, we had over 200 species of fish and 90-something species of coral and it was a very typical reef for that portion of the Barrier Reef.

"The proponent had decided it was dead on the basis of the area that he wanted to mine was on the reef flat, which is the part that's exposed at low tide and normally has only a very small amount of live coral on it.

Mining was nearly conducted on Ellison Reef. ( Supplied: Christopher Tilt, Birds Eye View Drone Services )

"That area, of course, contained a lot of coral sediment and if you mine in those sorts of areas, as we've seen since in South East Asia, you get big sediment plumes. They damage well beyond, well, well beyond the immediate area being mined."

The Premier, when pressed, did admit there were risks to mining the reef, but believed they were acceptable.

"There is a risk element in this as there is in you going across the street. A very big risk element with all the traffic that's there, and we've just got to accept it, I take it that you will," he said.

The Innisfail Court did not accept that risk, and mining on Ellison Reef was cancelled.

"It's an incident that instantly begins a war," said Dr McCalman, noting that the year spent battling for Ellison was the first of many years spent fighting to protect the Great Barrier Reef from development.

Ellison Reef is located off the coast of Mission Beach, in northern Queensland. ( Supplied: AIMS )

After almost 10 years of conservationist-led education campaigns and trade unionist threats of boycott, plus the bad publicity from disastrous oil spills overseas and bipartisan federal legislative action, the Great Barrier Reef Marine Park was created in 1975.

The reef was World Heritage listed in 1981, but its longevity is once again under threat, largely from climate change.

From left to right: Judith Wright, Arthur (Taff) Fenton, John Büsst . ( Supplied: Friends of Ninney Rise )

Over the last 30 years, it's been hit by a series of intense cyclones, major bleaching events from rising sea temperatures, crown of thorn starfish outbreaks and floods.

And a decline in water quality — the result of onshore activities like farming and deforestation — also poses other serious problems for the reef.

For people like Mr Hegerl and others concerned for the longevity of this natural wonder, the fight is far from over.

Four years before she died in 2000, Judith Wright wrote a new foreword to her book Coral Battleground, which still holds currency today: