The day the Captain died

At 4.45am on 5 November 1991, Robert Maxwell picked up the internal phone aboard his £20m yacht, the Lady Ghislaine, and called the bridge. Twenty minutes earlier he had phoned to complain that his cabin was too hot – could they turn the air-conditioning up? Now, it was too chilly. "The temperature is now too cold. Turn the air-conditioning off," he growled.

They were the last words he is known to have spoken. At 5.25pm the same day, a fisherman reported a body in the sea, some 15 miles from where Maxwell's yacht had been cruising when he moaned about the air-conditioning. A little over an hour later, a Spanish helicopter hovered overhead. "Naked, stiff and floating," was the matter-of-fact police description of the corpse of a man who, in life, was a bullying, monstrous figure – media mogul, tyrant, and corrupt wheeler-dealer.

What happened to "Cap'n Bob" between his call about the heating and noon, when the alarm was raised that he was missing, will presumably never be known for certain. Inevitably, the manner of his passing gave rise to speculation. Theories abound, some of them fantastic. Here are some of the most popular.

1) On the verge of financial ruin and probable disgrace, knowing that journalists were on his trail and bankers were losing patience with his financial juggling, aware he had finally run out of places to turn – and cash to steal – he killed himself.

2) Worried that Maxwell had come into possession of tapes indicating MI6's involvement in the murder of the Bulgarian dissident writer Georgi Markov, British security agents killed him.

3) Fearful that his activities on their behalf were about to be exposed, Mossad, the Israeli secret service, assassinated him.

4) He had a heart attack and drowned.

5) It was an accident, pure and simple.

A decade on, the fallout from Maxwell's death shows no sign of fading. Only this week, one of his business associates, Geoffrey Robinson, once the Paymaster General, was suspended from the Commons for three weeks over his behaviour towards a parliamentary inquiry into a payment to him from Maxwell. Labour remains acutely sensitive to any Maxwell connection. Once lauded as a key supporter, Maxwell is now seen as a pariah, a robber of pensioners' cash to furnish his lavish lifestyle. Unfortunately, several members of the Labour hierarchy were close to Maxwell, among them Robinson, Alastair Campbell, Helen Liddell and Lord Donoughue – not that they knew anything of his financial shenanigans, of course.

They, like other figures in the media and British public life, were shocked by Maxwell's death. The first reactions were ones of fulsome tributes. Only later, when details of his raiding of the pension funds emerged, did that give way to another kind of shock – a sense of betrayal and anger.

His family and closest business confidants have found it more difficult to argue that they did not know what he was doing. Two of his sons had to fight court actions to clear their reputations, but they will never shake off the Maxwell name. The former directors of his companies, and his bankers and advisers, have resumed their careers, with varying success – but the Maxwell link will never go away.

If he had lived, he would probably have gone bankrupt and his plundering would have been revealed, eventually. But his sudden passing, leading to the swift collapse in confidence in his companies and the calling in of accountants, made the exposure of his crimes a certainty.

His death, however, remains a mystery. Even now, remarkably little is known about it. He was 68, in poor health, weighing 22 stone and with a weak heart and lungs. Shortly before dawn, he left his cabin and went to the rear of the boat. He fell forward over a low rail and dangled over the water 10ft below. He clung on with his weaker left arm, tearing the muscles on that side of his body. Eventually, he tumbled into the sea, where he was found about 12 hours later. It was dark and the ship's engines were running. If he shouted and waved, the crew heard and saw nothing. He was naked, although it was later reported that his nightshirt was missing from his cabin.

An autopsy carried out in Tenerife found there was no sea water in his lungs, which would have indicated drowning. Instead, the pathologist, Dr Carlos Lopez de Lamela, concluded he died of a heart attack. Two days later, another examination was held. This time it was in Israel, where Maxwell's body had been flown for burial. In charge was Dr Yehuda Hiss, an Israeli pathologist. Also present was Dr Iain West, one of Britain's most eminent pathologists. There was evidence from badly ripped muscles and some internal bleeding that he had put up a struggle before plunging into the water. They could not examine his heart, which had remained in the laboratory in Tenerife. Dr Hiss thought Maxwell had suffered a heart attack and drowned. Dr West disagreed: there was no heart attack, Maxwell had fallen into the sea and drowned. Three pathologists, three different verdicts, one body.

The puzzle was fuelled by other findings. Maxwell's body appeared not to have the telltale signs of someone who had been in the sea a long time. His skin was not shrivelled from the exposure to sea water and he was not sunburnt. His nightshirt was missing. He was naked; but, the captain of the yacht would later claim, his cabin door was locked from the outside – so how had he planned to get back in? Surely, if he had just stepped out for some air or to urinate over the side – which he often did – he would not have locked the door.

If it was suicide, it was an unusual one. People who intend to kill themselves, apparently, like to do so fully clothed. And why did he cause himself agonising pain by clinging on to the side and shredding his muscles? Second thoughts? There are other indications that he did not take his own life. There was no note. The night his body was found, his cabin was cleaned and tidied by the crew so that his wife Betty could use it. If there were any clues lying around they were swept away.

Betty herself was adamant: he would never have committed suicide. "Impossible. He'd never do that," she said. She believed from the outset that it was death by natural causes. She had witnessed the physical changes in Maxwell down the years, from dashing soldier to bloated alcoholic, and knew he was on borrowed time. She was aware he had been found previously to have low oxygen levels in his blood. He suffered from heart disease and one lung did not function properly.

Besides, if he had been planning his death, why would he have been making arrangements to see people when he returned? His Gulfstream jet was waiting in Tenerife to fly him home. In his last conversation with a member of his family – with his son Ian at 10.40 on the night he died – he gave no indication of what was about to happen. "See you tomorrow," Ian said. "You bet," was Maxwell's reply.

Before that conversation, Maxwell phoned Derek Haynes, the former managing director of the Mirror Group in northern Britain, who had recently been forced to quit by Maxwell. A still smouldering Haynes refused to take the call.

Maxwell's last evening was spent alone. He ate a meal of fish and salad at a restaurant in Santa Cruz, Tenerife's capital. On the way back to the yacht he asked the driver to stop for a coffee. He talked about going to a cabaret but thought better of it. He returned to the Lady Ghislaine at 9.45pm, changed into his nightshirt, phoned Haynes, got no answer, then took a call from Ian and another from a rabbi who wanted to talk about a Jewish library project in Moscow. He moaned about the air-conditioning, and that was it.

Apart from the uncharacteristic isolation, there is no clue in this description as to what was really going on in Maxwell's life. And that is part of the mystery. He knew he had plundered his company's pension fund to prop up his finances. He was facing intolerable pressure. And yet, as Tom Bower, his biographer, points out in Maxwell: The Final Verdict, this was not new: "Anyone who had fought on the front line from the Normandy beaches to Germany, facing constant danger and death for months on end from the enemy's snipers and shells, was unlikely to suffer fear. And he had overcome much worse. The humiliation after the insolvency in 1954 of the publishing warehouse Simpkin Marshall, the excoriation heaped upon him in 1971 by the Department of Trade and Industry inspectors after the Pergamon disaster, and his triple defeat in the parliamentary elections of 1970 and 1974 had all been survived. He had fought back to be fêted by kings, queens, presidents and prime ministers. Despite all his enemies, he had, like Lazarus, risen from the dead. Having cheated Hitler and the Holocaust, he could survive, fight and win again."

So why didn't he? If you discount suicide, what of the murder theory? Maxwell only decided to go to the yacht on the spur of the moment. He was due to spend the weekend in Israel, on yet more meetings with political leaders and business contacts. He had a bad cold and told colleagues he was going away for a few days to get over it. So sudden was his visit that the yacht, moored in Gibraltar, was not ready.

At first, the Lady Ghislaine sailed to Madeira. The yacht was due to go to Bermuda for warmer weather, but on his instructions it went to the Canaries. He was due in London on 4 November to speak at the dinner of the Anglo-Israel Association. He decided not to go; Ian had to stand in for him. A hit squad planning to kill him and escape would have had difficulty keeping up with the changes to his plans.

That is not to say Maxwell was not concerned about his safety; he was. The Lady Ghislaine had security cameras at key points and the crew were under orders to keep watch on the gangplank when in port. At night the radar scanned for any vessels approaching. If he was murdered, the assassin or assassins would have had to get aboard, force him into the sea and escape – all without anyone hearing or seeing. If it was an inside job, again there was no sign. The crew were interviewed by an examining magistrate in Tenerife, Isabel Oliva, who found nothing suspicious. Two forensic examinations revealed no puncture marks on his body. There was some slight bruising, but nothing to indicate an assault.

If he was murdered, who would have done it? Speculation, much of it on the internet, centres on rogue elements in MI6 or the Israelis. Both theories are the stuff of the most lurid novels. Among the more sober details is the fact that, six weeks before he died, Maxwell was visited by the late Andrei Loukanov, the former communist prime minister of Bulgaria and one of the publisher's closest Eastern European associates. Loukanov had access to Bulgarian secret service files on the killing in London in 1978 of Georgi Markov, who was injected with poison, possibly from the tip of an adapted umbrella. According to rumours that refuse to go away, the Bulgarian files contained evidence linking the Markov murder with MI6. His assassination was planned by an agent working for both MI6 and the Bulgarians. The details of the Markov murder were contained in tapes and documents held by Bulgarian security. In later years, this rumour has it, MI6 made strenuous attempts to cover its tracks, including paying a Bulgarian official £50,000 to have the archive destroyed.

Loukanov is reputed to have copied the file and, so the story goes, delivered it as a favour to Maxwell, who subsequently kept it with him at all times. Terrified that he was going to pass the documents and tapes to journalists on his own paper, the Daily Mirror, MI6 agents are supposed to have tracked him to the Lady Ghislaine, forced him to open the safe and hand them over, and then forced him over the side.

The Mossad theory is equally lurid. This casts Maxwell as the keeper of Israel's dirty secrets, the Western "Mr Fixit" who disguised the funding of the country's top secret and diplomatically hypersensitive nuclear weapons programme through his businesses, and as a money launderer and arms buyer. Alarmed that Maxwell, whose behaviour had become erratic and who was desperate for cash, might be about to blow their cover, the Israelis silenced him.

Fantasy? Probably. Yet Maxwell is known to have made at least one vital contribution to Israel's nuclear industry. In 1986, the Sunday Mirror was approached with the inside story of Israel's Dimona nuclear weapons facility by an Israeli, Mordecai Vanunu, who had worked there. Maxwell took an obsessive interest in the story, working closely with the Israelis to rubbish the story and ordering staff to take Vanunu's pictures and documents to the Israeli embassy in London. Vanunu was later kidnapped by the Israelis, returned home and sent to jail, where he has been, mostly in solitary confinement, ever since.

Maxwell's betrayal surfaced shortly before he died, in October 1991, in a book by the American journalist Seymour Hersh. Maxwell's response to Hersh's The Samson Option was typical: he issued a writ. But this time his opponents did not back off. Hersh's claims were aired under privilege in the House of Commons, giving the green light to the media to repeat them. In interviews, Hersh went further, throwing in allegations of arms dealing.

Yet if Mossad really was afraid that Maxwell knew too much, what are we to make of the Israeli government's behaviour after his death? Maxwell was accorded the next best thing to a state funeral, with President Chaim Herzog intoning over his corpse as it lay in Israel's Hall of the Nation: "He scaled the heights. Kings and barons besieged his doorstep. He was a figure of almost mythological stature. An actor on the world stage, bestriding the globe, as Shakespeare says, like a colossus." At his graveside on the Mount of Olives stood Herzog, Yitzhak Shamir, Ariel Sharon and Shimon Peres, to name a few of the country's most powerful figures. For some, the turnout and Herzog's words testified that Maxwell had been a faithful servant to Israel in the darker recesses of power and arms.

Herzog's tribute was incredible, not only for the hyperbolic language but also for what it omitted. The Israeli president was not alone, however. World leaders, including John Major, George Bush, François Mitterrand and Boris Yeltsin queued up to sing his praises. His own paper did him proud, glorying in his life and achievements, hailing him as "the man who saved the Mirror". The night he died, Alastair Campbell, now Tony Blair's press spokesman, then the Mirror's political editor, was famously involved in a brawl with his opposite number at The Guardian, who had dared to mock Maxwell's demise.

Not everyone's verdict was so dewy-eyed. This newspaper's judgement was scathing. Maxwell was a "a liar, a cheat and a bully" who had done "more than any other individual to pervert the British law of libel", The Independent wrote. Few people suspected, though, just how much of a liar and a cheat he had really been.

The last few months of his life were a whirl of deception and dishonesty. Hideously overstretched, with borrowings of £2bn, his companies were running on empty. He was having to take from one side to pay the other. He had given shares owned by a finance company, First Tokyo Trust Corporation, as security on a loan from Swiss Bank Corporation for £55m; he had been stripping the pension funds of their investments to prop up his share price. The media were closing in – first Panorama, then Hersh, then the Financial Times probed his affairs.

Normally, Maxwell would see off such threats. As long as they got their cash, the bankers would be pacified – they were not to know where it came from. The press, too, would be silenced by a writ. But this was different. The cash was getting tighter and the banksless forgiving. Press coverage was increasingly emboldened. The FT, he knew, was methodically assembling a picture of the true state of his businesses.

So intense was the pressure that when Maxwell left, unannounced except to a few close aides, for his yacht to cure his cold, senior staff in London thought he had absconded. By then, Goldman Sachs, Lehman Brothers and Citibank, three of Maxwell's biggest financial supports, had had enough. Goldman sold some of its shares in his company, MCC, while Lehman was preparing a global default notice on loans worth £93m.

Citibank wanted $40m (£30m) it was owed. At one point a senior Citibank banker had refused to leave the office of one of Maxwell's senior lieutenants until the bank had its money. For a businessman like Maxwell, this was as bad it could get. The financial community would see Citibank's harder stance for what it was – a total loss of faith in Robert Maxwell. He knew this as he boarded the Lady Ghislaine. He knew, too, that on the morning of 5 November, the FT was due to quiz his son, Kevin, about what the paper had found. He knew these things as he stood on his yacht. Finally, as he clung on to the rail with his weaker arm, the fight went out of him.