The Baltic ferry Estonia had 989 people on board when it set sail from the Estonian capital, Tallinn, bound for Stockholm on the evening of 27 September 1994. In the early hours the next day, seaman Silva Linde, standing near the bow door of the car deck on routine watch, was struggling to keep his feet in the stormy seas. Then he heard a loud bang, which seemed to come from the port side. He reported the noise to the bridge but, hearing no other sounds, he continued on his rounds.
Shortly afterwards, as he stood by the information kiosk, the ship started rolling violently. All the money from the kiosk, which provided change for the casino, fell to the floor. Linde hurried towards the foredeck, where he found passengers running up the stairs. There was water on the car deck, they were shouting.
The Estonia capsized and sank in 45 minutes, going to the bottom in 250 feet of water, 20 miles south of the coast of Fin- land, at 1.48am. The 852 deaths made it one of the worst maritime disasters of the 20th century; there were just 137 survivors.
The Swedish government at first promised to raise the wreck and to spare no cost in finding the cause of the disaster. But then it changed its mind, refusing all pleas from the bereaved relatives to bring the Estonia to the surface, even though it lay in shallow waters. The subsequent Estonia Agreement 1995 sought to prevent any exploration of the wreck, which lies in international waters. The agreement was signed by Sweden, Finland, Estonia, Latvia, Denmark, Russia and, strangely, Britain, which has no obvious connection to the Baltic. One Briton, John Manning, died in the disaster; a second, Paul Barney of Pangbourne, Berkshire, survived after swimming to an upturned raft and clinging on in stormy seas until he was rescued.
Other non-Baltic countries with passengers on the ferry did not become signatories to the treaty. Two requests under the Freedom of Information Act to the Foreign Office in London, for background and briefing papers on why Britain signed the treaty, have produced no reply.
What caused the secrecy about the disaster and why was Britain so closely involved? The sinking of the Estonia has been an enormous story in Scandinavia - Sweden alone lost 500 people - but has received curiously little publicity in Britain and elsewhere. British involvement as a signatory to the treaty has gone virtually unquestioned. Until now.
I was investigating another story - about international smuggling - when a contact suggested I look at Britain's role in the Estonia affair. This man, a retired MI6 officer whom I have known for many years, told me that the sinking of the Estonia was not an accident and that Britain and the Baltic nations had good reason to want the wreck buried. Estonia (the country) had been used, he said, as a transit point to get sensitive military technology out of Russia and on to ferries heading for the west. Its relaxed borders and proximity to Russian military bases made it ideal for the task.
Despite the break-up of the Soviet Union, and the end of the cold war, the west still kept a close eye on Russian military capability, particularly its missile technology. (Of course Russia still had, and has, thousands of nuclear weapons.) One such smuggled shipment, of electronic guidance systems for missiles, had been on the Estonia when it sank. MI6 had been involved in the smuggling operation.
Later, my inquiries led me to an American businessman called Gregg Bemis. Bemis, aged 74, of Santa Fe, New Mexico, is an entrepreneur and venture capitalist and a former Republican Party congressional candidate.
He is also a diving and salvage expert who owns the still-submerged wreck of the British liner Lusitania, sunk off Ireland's coast in May 1915 by a German submarine, with nearly 1,200 dead, including 128 Americans. The attack helped bring the United States into the First World War. Bemis claimed sole ownership of the Lusitania by buying shares from those who had bought the ship from its insurer, and has led several expeditions down to its resting place.
His interest in the Estonia began in August 2000. After being asked by relatives of victims to investigate, he led a dive down to the wreck. It was harassed by the Swedish navy, which forced Bemis to sail from neutral Germany, rather than closer Sweden or Finland. This reduced the time his team could spend diving. The Swedes also despatched military speedboats to circle his ship, while coastguard officers boarded and demanded a crew list.
Warrants for the arrest of Bemis - and his partner in the expedition, a German TV producer called Jutta Rabe - were issued by the Swedish prosecutor. The treaty had made it an offence under Swedish law to dive down and explore the wreck - an offence carrying a maximum penalty of two years in prison. The US State Department warned Bemis to "back off" his investigation, and to this day he faces arrest and possible imprisonment if he ever sets foot in Sweden.
But Bemis's divers went ahead and found a hole near the bow. They filmed the wreck and brought up pieces of metal cut from near the bow door. Tests at laboratories in the US and Germany showed signs of an explosion on the ferry's hull. "The results show changes to the metal similar to those seen by high-detonation velocity," one report concluded.
The authorities in the Baltic nations insisted there was no explosion. There had already been an inquiry that they had set up. It had concluded in 1997, albeit after bitter disputes among its members, that faulty locks on the bow doors of the Estonia were the cause of the disaster, along with the crew's failure to react quickly enough to the crisis by reducing the ferry's speed. The 50-tonne bow door - battered by high seas - had been ripped off as the locks gave way, letting water flood into the car deck, and the ferry had become unstable and overturned, the investigation concluded.
The Swedish government, moreover, had hired divers from Rockwater, a British-based division of the American Halliburton group, run between 1995 and 2000 by Dick Cheney, now US vice-president. They produced 13 videotapes showing the wreck, they said, from every angle. But one angle was missing and some Swedish politicians argued that the videos had been edited. As Lennart Berglund, chairman of the Foundation of Estonia Victims and Relatives, said after Bemis's expedition: "There's still a lot of evidence down there. Their major argument was that there was nothing new - now there is something new." The Baltic nations, however, remained firm in saying there would be no new inquiry.
Last November, Lennart Henriksson, a former head of customs in Stockholm, confirmed my MI6 friend's story to Sveriges Television. The Estonia, he said, had been used for smuggling stolen Russian military equipment to the west. The shipments had been let through on orders from "the highest authorities". He had personally witnessed two such shipments.
The comments caused uproar in Sweden, and led to a fresh inquiry under Johan Hirschfeldt, president of the court of appeal. Bemis, armed with the results of his diving expedition, wrote to the judge but he, too, declined the opportunity to expand his inquiry. Hirschfeldt's investigation did confirm, however, that military equipment had indeed been carried on the ferry. There had been shipments just before the tragedy, on both 14 and 20 September 1994, as witnessed by Henriksson, and it had been a government operation. But, the judge concluded, the equipment was electronic and it had no connection to weapons systems. Hirschfeldt added, in a carefully worded statement: "There is no basis for me to assume that the defence authority of the defence procurement office [in Sweden] was trying to transport defence materiel on board Estonia when the ship sank."
So what caused the Estonia to sink, and who was responsible? The official inquiry's conclusions are simply not accepted by many marine engineers. Instead, investigators from Meyer Werft, the German shipyard that built the Estonia, raised the possibility of an explosion; the lab tests done on the material that Bemis's divers brought to the surface also showed traces of a detonation. This could explain the loud bang heard by Linde and others on board the ferry on the night it went down.
The evidence now points to Russian responsibility for the explosion. The Russian media have been investigating the story for years. One television report claimed that the Russian-Estonian mafia had placed a limpet mine on the hull - using a miniature submarine - to warn the shipping company that it should pay protection money. Other Russian journalists who tried to get to the bottom of the story, and who raised questions about the involvement of the Russian government, were warned by the authorities to back off. Russia, like Britain, has signed the agreement that prevents divers from exploring the wreck.
The most likely explanation is that British intelligence was behind the smuggling operation, working with the Swedes, and that a mine was placed by people acting for the Russian government in an attempt to stop them. The Russian mine was designed to prevent the Estonia from completing its journey, to damage it and force it back to port. The aim was to stop the specific shipment or the smuggling operation in general - or possibly just to issue a warning to western intelligence agencies. But the operation went wrong and the mine caused more damage than was intended, possibly because of the poor state of repair of the locks on the bow door. The ship sank and 852 people died.
The British and Swedish governments were secretly using public transport to smuggle stolen Russian military equipment. Did the Russians find out about it and warn them to stop? We may never know, but it is clear that the western intelligence agencies were taking a risk by using the Estonia, in effect turning the passengers on the ferry into a form of human shield. The major signatories to the treaty - Britain, Russia and Sweden - still have every reason to want the truth about the disaster buried.