DON'T PANIC! The enemy has anthrax, plague, botulism, poison gas, dirty bombs and ferries packed with TNT that make the Provisional IRA seem about as dangerous as Disgusted of Tunbridge Wells. But Mr Blair has announced that we should stay calm. Is he mad?
Last time, in 1997, I almost did panic. It was just after the weapons inspectors had unceremoniously left Iraq. The Daily Mail told us to expect hordes of Iraqi terrorists releasing anthrax from perfume bottles on the Underground. I was then, I suppose, terrified, as many are now. I had, I thought, good reason. Infections like anthrax and plague are directly within my field of professional interest. I knew what these bacteria could do. I was so worried, in fact, that I was about to evacuate my children to their grandmother for the duration - to the comparative safety of Belfast.
Then one morning I was cycling through Hyde Park, ruminating about who would really have inside knowledge on the real political, rather than medical, risks. Suddenly and surreally, as if by magic, Lord Hurd sprang into view just by the Albert Memorial. 'He'll know!' I thought. I pulled up next to him, and importuned him with my nervous inquiry. He asked where I lived, thought for a moment, and said, 'Stay where you are, dear boy.'
I took his advice and, of course, he was right. It seemed then that the old clichZ was true - what we had to fear most was fear itself. But 9/11 has changed everything, and has redefined terrorism in the same way that Hiroshima redefined war. We are up against a reckless and fanatical enemy who would stop at nothing. This time it's personal. The Home Office has blurted that we should expect a dirty bomb or a poison-gas attack in the coming weeks, then embarrassingly tried to unblurt it. Something is up; there are dark forces at work of which they have no knowledge.
So how real is the threat? Bioterrorism is nothing new. It was first recorded in the 6th century bc during the siege of Krissa, when Solon of Athens poisoned the water supply with a laxative called skunk cabbage. In 1797 Napoleon tried to force the surrender of Mantua by infecting the inhabitants with swamp fever. Throughout history there have been numerous and varyingly successful attempts to harness biology for warfare.
The problem with all biological agents, if you are going to use them for anything other than mass panic, is one of delivery. They work fairly well in sieges, where populations are trapped. If you are like Saddam and have total control of a region and can send crop sprayers to shower sarin over your immobile target population, then it also works pretty well as a weapon of genocide. There was some suggestion that the 9/11 pilots showed an unhealthy interest in crop sprayers. But mounting a logistics operation like that over a Western city would (now) be virtually impossible.
Attempts to unleash biological Armageddon so far have been remarkable for their ineffectiveness. In 1995 it was reported that on at least ten occasions the Aum Shinrikyo cult had attempted to disperse anthrax, botulinum toxin, Q fever, and Ebola against the population of Tokyo. Nobody noticed. In April 1979 in the city of Sverdlovsk, USSR, an explosion from Military Compound 19 resulted in a massive release of anthrax over the neighbouring population. Only 40 people are believed to have died. The thing about most of these agents is that, compared with crashing an airliner into a skyscraper, they just don't cut it.
There was, of course, the infamous poison-gas attack on the Tokyo underground, which was more successful. Twelve people died and more are still ill. In a grotesquely elegant manoeuvre, the terrorists unleashed the poison by placing plastic bags containing sarin on the floor of the train carriages, then pierced the lids with sharpened umbrella tips as they stepped off.
Horrible for the victims, indeed. But one could argue that a carefully placed ordinary bomb would have killed more. We in Britain with our history are supposedly blasZ about minor inconveniences like bombs - so much so that we can condescend to the dumb Yankees on the subject. Why are we so scared now? Somehow there is something more sinister about biological death, which is why it is such an effective weapon of terror. But such weapons only work through ignorance or exaggeration.
What about dirty bombs? The theory is that conventional explosives attached to radioactive material could render huge areas uninhabitable for generations. A carefully placed device could contaminate somewhere like the City of London and paralyse our economic life. But once again it is easy to overestimate the risks. There would certainly be deaths from conventional shrapnel. The concern, though, is cancer. The only comprehensive data for calculating radiation-based cancer risks comes from the surviving Hiroshima and Nagasaki populations. The problem occurs in extrapolating those cancer risks to the relatively low dose produced by a dirty bomb. You may actually need a threshold of radiation before you increase your risk, and such exposure may not be enough. In other words, the greatest danger from dirty bombs is probably not radiation, but the blind panic that such a bomb would generate.
So far so ...nearly reassuring. There are plenty of other potential biological, chemical and radioactive weapons whose descriptions could keep you awake at night, and I'm not going to do the terrorist's job for him. Besides, almost all of them suffer from the same logistical drawbacks. But there is one outstanding biological weapon that is in a league of its own. Unlike all the other agents, this one is spread from person to person, turning everyone infected into a weapon. It is virulently infectious with a high mortality among the unvaccinated - which means almost anyone born after about 1970. Vaccine protection wanes with age. It may go undiagnosed while infectious because the initial symptoms may be mild. One infected individual could spread the disease through an airport and contaminate most of the world within a few days. Experts disagree on the likely mortality but it could run into millions. That agent is smallpox.
Smallpox is a tried and tested biological weapon. By whom? Us, actually. In 1767, during the French and Indian war in Canada, Sir Jeffrey Amherst gave blankets laced with smallpox to Indians loyal to the French during the siege of Fort Carillon. The disease halved the local Indian population during the following years. The defector Ken Alibek tells us that the Russians cannot account for their smallpox stocks; almost certainly they modified them to overcome vaccine immunity. The Iraqis may have some; it is very easy to grow and disseminate. A smallpox rapid-reaction team is being created in Britain; as we already know, a vaccine - possibly the wrong one - is being stockpiled.
So why wouldn't al-Qa'eda use smallpox? Who knows? Maybe they don't have any. My guess is that they balk at the Pyrrhic nature of such a stroke - Jeddah and Islamabad would be affected just as much as New York and London. Perhaps even bin Laden has qualms about the indiscriminate slaughter of his own. Let's hope so.
Robert Baker is a doctor who has trained as a consultant in infectious diseases.