In the darkness of a winter night on July 10, 1985, twin explosions were heard from the waterfront in downtown Auckland. At Marsden Wharf, a trawler bearing the slogan "Nuclear Free Pacific" heeled and sank on her ropes.
So began an incident that reverberated around the world, brought down ministers in France and reinforced New Zealand's image, newly acquired in 1985, as a place where nothing nuclear was welcome.
That night in Auckland, skippers of a three-boat "peace flotilla" were meeting on Greenpeace's converted trawler Rainbow Warrior to coordinate their plans to sail to French Polynesia and protest at another season of nuclear weapons tests.
A few people were still on board at 10 minutes to midnight when the first blast shook the boat. It was soon followed by a second, much
louder, detonation that shook nearby buildings and blew a 2m sq hole in Rainbow Warrior's hull.
As the ship foundered, all but one of those on board jumped into the harbour or scrambled on to the wharf. Photographer Fernando Pereira died below decks.
The next day police briefed Prime Minister David Lange, who convened the Government officials' committee on terrorism comprising heads of the Security Intelligence Service, Defence Ministry and Chief of Defence
Staff among others.
The committee was chaired by the head of the Prime Minister's Department, Gerald Hensley, whose memoirs were published in 2006.
Hensley describes how the crime was traced to a French Government intelligence agency, the General Directorate of External Security (DGSE) which had, he says, "something of a cowboy reputation".
The day after the explosions, police told Hensley's committee that the Auckland Outboard Motor Club had been suffering vandalism and members were taking turns to stay overnight with the club's outside lights blazing.
The previous night the member on watch had seen a man in a diving suit and a red woollen hat paddle an inflatable dinghy up to the club ramp where he was met by a man and a woman in a stationwagon. Equipment was
loaded into the car and all three drove away.
The car turned out to be a rental and three days later police arrested a man and a woman when they returned it. The pair had Swiss passports in the same name, "Turenge".
Hensley writes: "They were held over the weekend and the bug we were rude enough to place in their motel room revealed, from the woman's anxiety not to take the marital deception too far, that they were not married."
He says the SIS quickly discovered the passports were false and had been issued in Lyons.
More clues were obtained from the inflatable left at Okahu Bay, from which all brands had been removed.
Its outboard motor was recovered from the harbour, along with sophisticated military diving equipment that released no air bubbles.
The "Turenges" turned out to a French Army major, Alain Mafart, and Captain Dominique Prieur, secret agents who were to become household names in New Zealand.
But they were just two of at least 10 undercover agents who had entered the country in the days or weeks before the sabotage. Some of them were not very careful.
The divers and their explosives had arrived on a yacht, the Ouvea, chartered from New Caledonia. It had put in at Parengarenga Harbour in the Far North to transfer the gear to the stationwagon, which was then driven to Auckland.
At Parengarenga dozens of people had noticed them. Hensley writes: "In the easygoing Northland fashion they were assumed to be smuggling drugs."
Their car journey attracted just as much attention.
"At lunch in Whangarei they flirted with a waitress who was delighted to recall them. Elsewhere they inquired about night lights for a Zodiac ... A roadside rendezvous was noted; even when they stopped in a forest
clearing at Kaiwaka a passser-by remembered one and possibly two outboard motors in the car.
"Most entertaining of all," Hensley recalls, "they turned out to have stayed on three occasions, the last the day before the bombing, at a motel near Helensville that was part-owned by David Lange."
The Ouvea back to Noumea from Whangarei the day before the blast. When it put in at Norfolk Island, New Zealand police were waiting and searched it but had no grounds to detain it. By the time evidence of explosives was found in its bilge water samples it was near New Caledonia.
On intercepted radio messages the yacht reported it had "problem" and talked about a rendezvous. New Zealand sent an Orion to make sweeps of the ocean but did not find it.
Subsequent information, Hensley says, suggested the yacht was scuttled and the crew taken on board the French nuclear submarine Rubris, which was known to be in the area.
The incident became big news in France, with a little help, Hensley reveals, from "talkative sources in the New Zealand police".
An official inquiry that admitted the role of the DGSE but exonerated the Government and the agents, was dismissed in Paris as a whitewash.
In September, Prime Minister Laurent Fabius admitted the DGSE was acting under orders and his Defence Minister, Charles Hernu, resigned.
In November Mafart and Prieur appeared in the High Court at Auckland under intense security and pleaded guilty to charges of manslaughter and wilful damage.
In France the pair were seen as scapegoats, acting under orders, and newspapers called for their return.
Chief Justice Sir Ronald Davison sentenced Mafart and Prieur to 10 years imprisonment. They had participated, he said, in "an affront to the sovereignty of this country".
Within days Lange was rejecting French requests for their deportation. New Zealand's legal system was not "for sale", he said.
In the new year, New Zealand meat and potatoes were shut out of New Caledonia. Lamb brain exports to France were hindered without explanation. Fish, canned kiwifruit and urea were the next to face unspoken trade retaliation.
French voters changed their Government. The new Prime Minister, Jacques Chirac, had campaigned for the agents' return.
In June the two governments agreed to arbitration by United Nations Secretary-General Javier Perez de Cuellar, and on July 7, three days short of a year since the sinking of the Rainbow Warrior de Cuellar ruled that the agents should be transferred to a French Polynesian atoll called Hao and held there for three years. France would pay New Zealand $13 million in compensation for the crime.
Mafart and Prieur left New Zealand by Orion on July 23 and were handed to French authorities on Wallis Island, who greeted them with hugs and kisses according to the Orion crew.
Late in 1987, after Lange's reelection, Mafart was spirited back to France allegedly for medical treatment.
Prieur, who had given birth on Hao, remained there until May 1988, a few days before a French presidential election.
Her release was seen as a late boost to the campaign of candidate Chirac.
Meanwhile, the wreck of the Rainbow Warrior had been sent to the bottom of Matauri Bay in Northland. Its name is still a reminder that this country's borders are vulnerable and its security can be violated.