Cause of death: "Asphyxia from blocking of bronchi. Misadventure" (official death certificate), or "Poisoning by nerve gas"(Ministry of Supply court of inquiry)? The death of the 20-year-old RAF serviceman Ronald Maddison, a volunteer at the Chemical Defence Research Establishment, in May 1953, has returned to haunt this secretive unit on Porton Down. Today, Porton is part of the Defence Evaluation and Research Agency, complete with website and mission statement. Whatever goes on there now, Porton intends to stay; it has recently spent £3.5m of our money on a new gas chamber. What did happen there between 1916 and 1970 is finally becoming clearer, thanks to the release of documents at the Public Record Office and the diligence of investigators such as Rob Evans. When the Wiltshire police have finally finished their inquiry into the Maddison tragedy, we may learn even more, particularly about the experiments carried out on service "volunteers" in the 1950s and 1960s.
Gassed left me asking two main questions. Was the chemical defence work at Porton more secret than it needed to be? And were volunteers ("observers", in Porton-speak) truly voluntary as that came to be defined in the wake of the Nuremberg trials in 1947? (The Nuremberg Code spelt out, in a way that has yet to be bettered, the basic principle that human experimentation must be preceded by voluntary informed consent.)
Porton is a place of secrets in a country obsessed with them, and the answer to the first question has to be yes. Because of that, many of those who took part in the experiments could not have given fully informed consent, so the answer to the second question may be no. If those volunteers were sometimes actively misled, as alleged here, the consequences could be serious, even after all these years.
In early 1969, the Lancet decided that doctors ought to know something about CS gas, then being used in Northern Ireland. I had sketched its chemical structure to accompany the piece when an outside helper wondered if even that elementary item of information might have been an official secret. (C and S, by the way, are the initials of the chemists who first synthesised the compound, and that tells you nothing.) Even today not all the scientists who worked with, or were exposed to, CS (as well as other, far more dangerous chemicals) and who were willing to talk to Evans have actually done so on the record.
To understand the culture of Porton, we need to go back to that dreadful day at Ypres, in 1915, when the wind direction at last allowed the Germans to release chlorine gas across the Allied trenches. Phosgene and mustard gas followed. Once an urgent British research programme was under way, the military possibilities of chemical warfare blended sometimes imperceptibly into experiments designed to protect people from it. The fears were very real. The controversial and articulate geneticist J B S Haldane, very much a man of the left for his time, vigorously defended chemical warfare in 1925. The masks in those funny cardboard boxes hung by a string around the neck during the Second World War were a legacy of that reasoned fear, one that prevailed well into the cold war years. And people were different then. Authority, any authority, was respected. Porton was needed, and its volunteers made an important contribution.
Evans is aware of the danger of hindsight, and some of his interviewees reminded him not to condemn by today's standards. That is why I focus on those who volunteered between the late 1940s and early 1960s, by which time the establishment had in place an ethical oversight committee - whose scrutiny is now as good as can be expected, given that Porton will never be a university hospital.
No doubt there was an element of coercion of Porton volunteers, and it is more than likely that the experiments were not explained in the detail expected today. Evans disappoints, at the level of original documentation, in respect of one allegation. Were volunteers from the army and air force (the navy remained aloof) deliberately misled into thinking they were going to Salisbury Plain to be exposed not to nerve gases and the like, but to common cold viruses? From 1946, the Medical Research Council had its common cold research unit near by, and several of the serviceman whom Evans interviews are sure that this is what they saw on the noticeboards, and to which they had responded out of a sense of patriotism or boredom. This explanation is denied, as you might expect, by official spokesmen, and I, too, find it unlikely.
David Sharp is deputy editor of the Lancet