Synopsis

He crouched silently in the undergrowth, his presence obscured by the spring growth on the azaleas. The plan is good and simple, made easier by the man on the inside. He made his way stealthily through the side entrance, left unlocked by his accomplice, and grinned slyly. The task is easy now; water purification plants are a low-risk target and security is relaxed. He makes his way towards his target destination and, removing a small container from the cavity in the heel of his shoe, he extracts the capsule. In a second it is in the water supply and begins to dissolve. The toxin will be released in a matter of minutes and fed into the homes of almost 100 000 inhabitants of Oxford, including the elite academic community. Just enough time to make his retreat.

Scenario: 2002

It has been a good, hot spring and the professor strolls across the quadrangle to meet his colleagues for lunch. The dryness at the back of his throat made him walk a little quicker. Greeting his colleagues warmly he sits and pours water into four glasses, and drinks deeply, quenching the thirst of the dry spring day. Time passes quickly.

The afternoon seems hotter now, and the thirst grows stronger. The palms are wet and fever is setting in. Beads of sweat form on their brows and the throat becomes ever more dry. The abdominal cramps are excruciating, and the intense waves of nausea become unbearable.

Thousands more were suffering the same symptoms when they arrived at Oxford's City Hospital. The staff were disoriented by the weight of numbers in casualty, and more were arriving by the minute. Clearly, there is an outbreak of some kind, but of what? And what action can be taken?

The professor vomits and passes out.

Day 1
Oxford Hospitals report massive increases in numbers of patients and are quarantined. The country's foremost experts on tropical diseases and bioterrorism are despatched to Oxford. Thousands are admitted to hospital and 32 are confirmed dead due to vascular collapse.

Day 2
It is looking increasingly likely that this is an act of terrorism. As a precaution, the water treatment facility is closed for tests. The death toll rises to 963 as more succumb.

Day 3
After drifting in and out of consciousness for two days, the professor finally comes round. The chronic diarrhoea and severe abdominal cramps have taken their toll and the fierce fever has broken, leaving a nasty headache and a dry, burning throat. The mêlée around him continues. Two of his colleagues died today and his wife and twin daughters are in intensive care.

The water plant's preliminary report confirms the presence of a biological agent in the water, but definitive identification is still some days away.

Death toll 2997 and rising.

Day 7
Death toll at 4219. The situation has eased and the hospitals report few new cases. The professor goes home to his wife and daughter. One of the twins died on day 6. She was three. It has now been confirmed that the biological agent in the water was ricin.

Scenario: 2006

The new toxin detection system has been in use at the water treatment facility for six months now. A unique piece of equipment, it extracts a sample of water every two minutes and adds genetically modified bioluminescent bacteria. If contaminants are present, the bacteria's light output decreases in direct proportion to the sample's toxicity and the water supply is shut off automatically while the sample is analysed further. In a matter of minutes, an artificial neural network identifies the toxin and determines the toxicity of the sample.

Death count: zero.

Comment

My research using bioluminescent bacteria and artificial neural networks, although at an early stage, has shown that it is possible to identify and quantify contaminants in water in as little as two to three minutes. This is in stark contrast to more conventional methods, which often take several months to make an identification. The research represents a major breakthrough in the fight against terror, and also in toxicity testing of foods, cosmetics, drugs, groundwater and industrial discharge to rivers.

See also

• Wellcome Trust-New Scientist Science Essay Prize: Further information