Ian Burrell says that doctors now believe the drug contributed to Gulf war syndrome, the inquiry into which was overseen by Mr Soames.
Grandson of Sir Winston Churchill and Minister for the Armed Forces, Nicholas Soames stood up in the House of Commons last December and apologised for misleading Parliament.
He admitted he had understated the degree to which British troops were exposed to chemicals in the Gulf war and blamed the error on his civil servants.
"The evident failures in providing proper and timely advice to ministers are a matter of serious concern," he said. The Government, Mr Soames assured the House, had "nothing to hide".
Yet there was one intriguing piece of information which the minister did not to reveal to the House or indeed to the Commons Select Committee on Defence, which was demanding answers on the causes of an illness that has affected thousands of British troops.
At the time of the outbreak of the war, Mr Soames was a non-executive director of the Hertfordshire-based company, Hoffman La Roche (UK), the British arm of the Swiss chemicals giant.
The company had developed the use of pyridostigmine bromide as a safe treatment for the rare nerve disorder myasthenia gravis. Army medical chiefs were convinced that it could be used to protect the central nervous system from attacks by chemical weapons.
Hoffman La Roche supplied pyridostigmine bromide to the Dutch company Solvay Duphar which turned it into tablets for Nato. Although the drug had never been licensed for use on healthy people, or in the doses proposed, British and American troops were told to take what became known as "Naps" (Nerve Agent Pre-Treatment) tablets every eight hours. Doctors who have researched Gulf war syndrome believe that the tablets, safe in their own right, inter-reacted with the cocktail of vaccines, pesticide sprays and possibly chemical warfare agents that the troops were exposed to.
The veterans reported chronic fatigue, memory loss, and breakdowns in their immune systems. Dozens have died.
None of which could have been predicted back in 1991 after the apparently successful conclusion to the war. Mr Soames entered his directorship in the Register of Members' Interests. The company, now called Roche Products Ltd, said Mr Soames had been a non-executive director from 1988 until 1992 when the MP was appointed a parliamentary secretary at the Ministry of Agriculture and was obliged to give up his directorships. He was appointed armed forces minister in 1994.
In August 1993, pyridostigmine bromide was finally licensed for use on healthy people as a protection against chemical weapons. It was only around that time that the notion that Allied troops had emerged relatively unscathed from Operation Desert Storm began to be revealed as a fallacy and doctors began to accept that something was seriously wrong with the health of many veterans.
Goran Jamal, a neurophysiologist at Glasgow University, who has carried out extensive testing on the causes of Gulf illnesses, said: "I am certain that pyridostigmine bromide played an important role."
Richard Barr, a Norfolk solicitor representing hundreds of sick veterans, said: "The tablets were being blamed for playing a part in these illnesses from very early on. Mr Soames should have known they were developed by Roche and he should have made clear to the Commons select committee that he had an interest in one of the manufacturers of one of the prime suspects for Gulf war illness."
Mr Soames said that he was not aware that Roche made pyridostigmine bromide. "I had no idea it was even made by Roche," he said. "Plainly if I had I would have declared an interest."