It's impossible to estimate how many lives he has saved during his 30-year crusade against chemical weapons; a campaign waged with calm tenacity from a lab in Leeds University.

Prof Hay, one of the leading figures in the university's faculty of medicine and health, was an outspoken lobbyist in support
of the introduction of the Chemical Weapons Convention, which has been adopted by
182 countries.

He has now won a competition to find the most significant research project carried out by the university. The entry supplied by Prof Hay was always going to be a prime candidate for the top prize, although it faced stiff competition from academics who had worked to save rain forests and improve public transport.

Prof Hay's work stems from an abhorrence of chemical warfare that stretches back 30 years. Today, he feels his life has turned full circle as he helps chemists and companies to work within ethical boundaries.

Originally from South Africa, where he was a vociferous opponent of apartheid, Prof Hay began his work in the early 1970s, studying the effect of herbicides used by the US government during the Vietnam war. His first trip to Vietnam
was a revelation.

"I was overwhelmed by the extent of the damage in Vietnam. The Vietnamese believed the chemical and its contaminant had caused malformation in children. They were concerned about the cancer risk. To this day, sadly, the evidence on both of those is very unclear. The Vietnamese still maintain that Agent Orange has caused birth deformities but the clear, definitive studies that would pinpoint this chemical as the cause of the malformation have never been done, and now it's a bit late for that to happen. The cancer risk for the population, again, has not been properly assessed."

Following his investigations, Prof Hay was invited by the US Environmental Protection Agency to produce guidelines on human exposure to the dioxin family of chemicals.

In the early 1980s, the danger of a war in Europe between Nato and the Warsaw Pact countries involving the use of nerve gases and other toxic chemical agents, became a real threat, and Prof Hay campaigned to persuade scientists not to engage in research leading to the development of these weapons.

"I felt this was the very antithesis of what they ought to be doing," he says. "Chemical warfare came out of chemistry. It wasn't low-grade scientists who were involved in this area. It was people at the peak of
their profession. Times have moved on, and that sort of thinking is not prevalent among chemists today.

"Chemical warfare did look like it would become a reality in the 1980s, and had it been used, there could have been millions of casualties among civilians. This really was one of the major rationales for campaigning against it."

Many conspiracy theorists believe conflicts are driven by a sinister military-industrial complex. But, according to Prof Hay, the chemical industry played a noble role in making chemical warfare less likely.

He recalls: "The US was trying to modernise its arsenal of chemical weapons in the 1980s and we were campaigning against this. When they were trying to modernise, what
they needed was a chemical company to make the chemicals. None of the big chemical companies would touch it.

"One of the reasons we came up with a chemical weapons treaty is because the chemical industry put pressure on governments."

He is perhaps understating his own role. In the early 1990s,
he and a number of fellow scientists signed a petition setting out their objections to chemical warfare. Most nations have signed up to the resulting treaty, which has been instrumental in leading to the destruction of vast arsenals.

Prof Hay has continued to encourage governments to
sign treaties to outlaw the use
of chemical and biological weapons and investigate their alleged uses. This brings us to Iraq, and the West's confrontation with Saddam Hussein.

Prof Hay recalls: "Before the first Gulf War, there was clearly evidence that the Iraqis had chemical weapons because they had used them against the Iranians. After Iraq's defeat,
the United Nations sent in expert teams to dismantle
their infrastructure for making chemical weapons and subsequently biological weapons.

"When we had the second Gulf War, and Tony Blair and George Bush were talking about Iraq having these weapons, colleagues and I pored over information that was coming out of Iraq. There were some people who had a vested interest in Saddam Hussein being overthrown who were saying that Iraq had these weapons. There was no evidence that Iraq was
making these weapons and had this capability."

Did some of the claims made by the Government in the
run-up to the war in Iraq surprise him?

"Yes, totally. The Iraqis didn't have these weapons. The belief that we went to war to stop Iraq threatening us with weapons was false."

He was a friend of the weapons expert Dr David Kelly, whose tragic death triggered the Hutton report.

Prof Hay recalls. "David Kelly was a very modest man, but he had a huge knowledge. There wasn't a biological scientist in the UK who had his expertise. The Iraqis feared him because he was so persistent."

On July 17, 2003, Prof Hay received what was possibly
Dr Kelly's last message to a colleague before he left his Oxfordshire home, removed his watch and spectacles and bled to death from wounds to his left wrist. Dr Kelly's email thanked Prof Hay for his message of support. He had just been questioned by MPs and others as the alleged source for the BBC's claims that the Government dossiers over Iraq's weapons of mass destruction had been "sexed-up" to justify going to war.

The Hutton report cleared the Government of wrongdoing but criticised the BBC for "defective" reporting. Lord Hutton found that the BBC had reported "unfounded" allegations that Downing Street had "sexed-up" the dossier and failed to properly investigate complaints from the Government.

It also ruled that Dr Kelly took his own life.

Although he shares Lord Hutton's belief that his friend committed suicide, Prof Hay thinks the report was flawed: "What happened to him (Dr Kelly) was an absolute tragedy. He clearly had concerns about the war, and that is why he was talking to journalists. He would have known that he ran a risk in doing this. I did feel the Ministry of Defence didn't show the
duty of the care that it should have done for a man who had served them so well. I felt it was an outrage.

"There were various issues that came out after David Kelly's death; lots of conspiracy theories that he had been murdered by different people and so on. Partly, this was because Hutton did not provide the sort of forensic enquiry that a coroner would have done. A coroner would have had individuals cross-examined – every bit of evidence would have been turned over, and different experts would have been called until you got a clear view, and, because that didn't happen, I think the enquiry missed an important trick in relation to the way that David Kelly died.

"I also feel that it was outrageous in that it let the Government off the hook and said the BBC was to blame for all sorts of issues."

Today, Prof Hay is proud to note that the chemical weapons treaty is proving effective, but he believes that the chemical industry must be vigilant to ensure there are no ethical lapses.

"This means having a responsibility to the environment and to your employees. It's about reducing the amount of waste you produce and ensuring that your products are safe. This is going to require a lot of expertise, so universities have a lot to contribute. And the business community is recognising that it has to have a code of ethics.

"The University of Leeds is very keen to develop some of the academic findings into business opportunities. Academics like to be able to pursue problems in a particular way and business is focused on producing a product that will sell. You can marry the two,
and although the marriage can be a bit bumpy on occasions, there are opportunities for
both of them."

Deputy Business Editor Greg Wright spoke to Professor Alastair Hay
from Leeds University.