Professor John Henry, who died on May the 8th 2007, aged 68 years of age was one of the world's leading authorities on drugs and poisons; his frequent appearances on Television and Radio made him Britain's best-known Toxicologist and after his retirement in 2004, he continued to work as a medical expert, sought after around the world.

When, in September 2004, the Ukranian opposition leader Viktor Yushchenko fell seriously ill - and mysteriously ill - during the election campaign, Henry was sent a photograph of the patient and immediately concluded, due to the characteristic pattern of acne, that Yushchenko had been poisoned by Dioxin.

This had been missed by the Doctors who had examined Yuschenko in Vienna, but a month later they confirmed the diagnosis. Henry was also called in as an advisor in the more recent cases of the former KGB agent Alexander Litvinenko and Pakistan's cricket coach, Bob Woolmer. It was characteristic of him that he did not charge for these services.

As Professor of accident and emergency medicine at Imperial College, London, Henry broke new ground in the management of poisoning and drug overdose, helping to save the lives of many patients. He was also Honorary Consultant in accident and emergency medicine at St Mary's, Paddington, and visiting Professor to the Radcliffe Infirmary, Oxford. John Henry was also registrar of Guy's Hospital in the 1980's.

Having suffered as a patient on dialysis for more than seven years, he exhibited great compassion to all the patients in his care. In 1982 he was appointed consultant physician at the National Poisons Unit at Guy's Hospital, where he saved a great many lives, particularly those of children who had accidentally ingested potentially lethal household products. He carried out research into how poisons worked and how they could be counteracted.

Henry had the ability to explain complex medical matters in simple terms and had an encyclopaedic knowledge of drugs and poisons. A typical story is of the occasion when he was in the resuscitation room attending a patient suffering from a drug overdose. When a colleague asked Henry why the patient's urine was green in colour, he immediately replied that the patient had obviously taken the drug Rohypnol. Tests proved this to be so.

He was especially concerned about the devastation wrought on young lives by illegal drugs. He insisted that cannabis was much more dangerous than simple tobacco; it eroded users' volition, drive and dignity, destroying the personality and having devastating effects on society. He would also explain how Ecstasy and amphetamines could cause death through hyperpyrexia and dehydration. He was one of the first to warn that the risks of taking Ecstasy had been underestimated and such were his vivid descriptions of the results of nightclub abuse, that at one stage he was known colloquially as Mr E. He was an expert witness at the inquest into the death of Leah Betts, who died after taking an Ecstasy tablet at her 18th birthday party in 1995 and whose case became a cause celebre.

John Henry was born at Greenwich, London on March 11th 1939, the eldest of four surviving children, Siobhan, Gabrielle, Michael, and a fifth Desmond, died in infancy in Charlestown during the second world war. His late father John (Jack) Henry, who was a General Practitioner in Greenwich, was born in Charlestown in 1898 and studied in University College Dublin in the mid 1920's with the late Kevin Barry. He won a Sigerson Cup medal in 1923 with the College team and played with the Mayo senior team in the infamous All-Ireland final of 1925.

John Henry's Grandfather, Mark C Henry, 1854 - 1952, was a Cumannn na nGael TD, from 1927 to 1932. He attended St Joseph's Academy, Blackheath, London and went on to study medicine at Kings College, London. As a 20 year old medical student he joined Opus Dei as a 'numerary member' committing himself to a life of celibacy.

In the 1960's while on holiday in Italy, John caught a throat infection which was inadequately treated and this lead to kidney failure. It was highly unlikely that he would live long as a dialysis patient and he gave up medicine for five years. The then head of Opus Dei, Mgr Josemaria Escrival, now St Josemaria, prayed fervently that a suitable kidney could be found for a transplant. In 1976, shortly after Escrival's death, a perfectly matching kidney was found and a successful operation gave John a new lease of life.

John Henry is survived in Charlestown by his aunt, Mrs Delia Henry, wife of the late Tony Henry, his cousins Cathal and John, and in the USA by his cousins, Tony Henry, Hilary Heaney and Mairead Salens, and in Portadown by Brian Henry. John also had a cousin in Letterkenny, the late Michael Henry.

May he rest in peace.

© Cathal Henry