Peak displayed a series of slides from an electron microscope. They showed different types of microbe. Some looked like star-shaped amoebas, others resembled scaly or bristly spheres, while the rest were hamburger-shaped, with twisted tentacles extending from between the two halves of the bun.

'These are all pictures of Pfiesteria,' said Peak. 'It can change its appearance within minutes, growing to ten times its former size, encasing itself in a cyst or mutating from a harmless single-cell organism to a highly toxic zoospore. There are twenty-four different shapes that Pfiesteria can assume, and with each different shape comes different characteristics. We've now succeeded in isolating the toxin it produces, and Dr Roche and his team have been working flat out to pinpoint its chemical structure, but they face even greater difficulties than the scientists in the States. The organism contaminating Central Europe's water supply isn't Pfiesteria piscicida, but another, far more toxic strain. Pfiesteria piscicida means "fish-eating Pfiesteria?" Dr Roche has christened the new species Pfiesteria homicida. "Man-eating Pfiesteria"?

Peak summarised the factors that made tackling the algae so difficult. The new organism seemed programmed to reproduce in cycles of explosive growth. Once it had entered the water supply, it was impossible to get rid of. It seeped into the soil and deposited its toxins, which resisted all efforts to filter them out. And that was the problem. It was bad enough that many of the algae's victims were literally covered with Pfiesteria cells, which were eating them alive. Angry sores opened on their bodies, becoming infected, gangrenous and refusing to heal. But the poison given off by the algae was even more of a threat. No matter how determinedly the authorities tried to clean water-pipes and tanks, the organisms turned up elsewhere and spread their toxin. They had tried fighting them with heat and acid, clubbing them to death with chemical cudgels, but they had to be careful not to substitute one evil for another.

Pfiesteria homicida seemed unconcerned. Pfiesteria piscicida affected the nervous system, but the new strain attacked it with such aggression that it was paralysed within hours. The victims fell into a coma, then died. Only a few people seemed immune to it. Since Roche had been unable to unravel the structure of the toxin, he was hoping to decode the genetic basis for immunity, but time was running out. The epidemic had spread so fast it seemed impossible to stem.

'The algae arrived in a Trojan horse,' said Peak, 'tucked away in crustaceans. Trojan lobsters, if you like – or, at least, they looked like lobsters. The creatures were clearly alive when they were caught, but their flesh had been replaced with a jelly-like substance, inside which the colonies of Pfiesteria were hiding. The European Union has now outlawed the catching and exporting of lobsters. At present, only France, Spain, Belgium, Holland and Germany have reported instances of sickness and death. The latest available figures listed fourteen thousand fatalities. American lobsters still seem to be the real McCoy, but the authorities are contemplating a ban on the sale of crustaceans.'

'Dreadful,' whispered Rubin. 'Where did the algae come from?'

Roche turned round. 'We created them,' he said. 'Liquefied pig faeces are flushed into the sea by the east coast hog farm industry. Pfiesteria flourishes in fertile waters. The cells feed on phosphates and nitrates from the animal dung that washes off fields and into the rivers. They like industrial outlets too. It's obvious that they'll feel perfectly happy in city sewers where there's plenty of organic matter to go round. We're responsible for creating the Pfiesteria of this world. We don't invent them, but we allow them to turn into monsters.' Roche paused and turned to Peak. 'Take the Baltic, for example. If things get much worse, the fish will be wiped out, and it's obvious who's to blame – the Danish pig-rearing industry. Liquid manure prompts algae to bloom exponentially. The oxygen level of the water is depleted, and fish start to die. But these toxic algae are going to do a damn sight more than kill fish, and nowhere seems safe from them. We've got the deadliest strain of all in our midst.'

'But why didn't anyone do anything about it before?' asked Rubin.

'Before?' Roche laughed. 'Oh, they tried, my friend. They tried.

Where have you been all this time? No, instead of being encouraged to continue their research, the scientists were laughed at. Their lives were threatened. There was a scandal a few years back when it turned out that the environmental authorities in North Carolina hushed up the cases of Pfiesteriato appease various influential politicians who also happened to be pig farmers. Of course, there's always the question as to which lunatic is sending us Pfiesteria-contaminated lobsters in the first place, but the fact remains that we helped give birth to this catastrophe. Somewhere along the line, we're always to blame.'

'THESE MUSSELS HAVE all the characteristics of a zebra mussel, but they can do something that ordinary zebra mussels can't. 'They navigate.'

Peak had progressed to shipping accidents. 'The delegates had only just ploughed their way through Pfiesteria growth curves, and now they were being presented with another set of devastating statistics. Coloured lines criss-crossed the world.

'Shipping routes for merchant vessels,' Peak explained. "The key to the whole thing is the redistribution of transportable goods. As a rule, raw materials are shipped in a northerly direction. Bauxite is exported from Australia, oil from Kuwait, and iron ore from South America, travelling distances of up to eleven thousand nautical miles to either Europe, North America or Japan, where the raw material is taken inland to cities like Stuttgart, Detroit, Paris and Tokyo, and turned into cars, electrical equipment and machines. 'The commodities are then loaded into containers and shipped back to Australia, Kuwait and South America. Nearly a quarter of world trade passes through the Asian Pacific. 'That's a total value of five hundred billion US dollars. A similar amount is shipped through the Atlantic. 'The busiest routes are marked here in bold: the east coast of America, including, most importantly, New York, then northern Europe – the English Channel, the North Sea, the Baltic Sea and the Baltic states – and finally the Mediterranean, in particular the Riviera. European waters play a pivotal role in world trade. Besides, the Med provides the passage from the east coast of North America through the Suez Canal to South Asia. 'Then there's Japan and the Persian Gulf, not to mention the China Seas, which rank just behind the North Sea as the busiest waters in the world. To get to grips with international seaborne trade, you have to understand the networks. You have to know what it'll mean for one side of the world if a container ship sinks on the other – which production chains will be disrupted, whose jobs are at risk, whose livelihood, or maybe life, is endangered, and who, if anyone, might profit from the mess. Air travel brought an end to the age of passenger shipping, but world trade still relies on the seas. Our maritime routes are essential.'

Peak paused.

'A few figures for you. Every day two thousand vessels pass through the Strait of Malacca and other nearby waters. Nearly twenty thousand ships of all shapes and sizes cross the Suez Canal every year. Each of those regions carries fifteen per cent of world trade. Three hundred ships a day make their way along the English Channel en route to the North Sea, the most congested sea in the world. Roughly forty-four thousand ships every year connect Hong Kong to the rest of the planet. Countless freighters, tankers and ferries circumnavigate the globe, to say nothing of the fishing flotillas, cutters, sailing-boats and sports boats. Millions of journeys are made through the oceans, marginal seas, channels and straits. Given all that, it probably seems unreasonable to suggest that an occasional supertanker accident could seriously threaten world trade. Surely a little thing like that wouldn't stop anyone filling their ramshackle tankers with oil? You see, most of the seven thousand oil tankers in the world are in a god-awful state. More than half have been in service for over twenty years, and most aren't worth the metal they're made of People in this business aren't afraid to take risks. There's always a chance that disaster could strike, but they're used to that. So they do their sums and ask themselves, What if it all goes right? They calculate the odds, and the rest is a gamble. If a three-hundred-metre-long tanker sinks into the trough of a wave, its hull can be warped by up to a metre. That's an enormous strain for any structure. But the tanker sets sail because, according to their calculations, things will be OK.' Peak gave a thin smile. 'But those calculations mean nothing when accidents start happening that can't be explained. They can't assess the risk. A different kind of mindset comes to the fore. We call it the shark-attack syndrome. No one knows where the predator's lurking or who it might eat next, so a single shark is enough to stop thousands of tourists swimming in the sea. Theoretically, it's impossible for one man-eating shark to have any real impact on tourism, but in practice the effect can be ruinous. So, imagine a shipping lane that's seen four times as many accidents in the space of a few weeks than ever before, and with no discernible cause. Ships are being sunk by alarming phenomena for which there's no explanation, and even those in tip-top condition aren't safe. No one knows which might be next and what measures they could take to safeguard it. There's no more talk of corrosion, storm damage or navigational errors. The word on the street is: don't set sail.'