Bolton School old boy Dr Nick Gent talks about the Salisbury nerve agent attack

Old boy Nick Gent went back to Bolton School to speak about the incidents in his capacity as deputy head of Public Health England's Emergency Response Department.

He told how he and the small team of medical advisors has played a key role in most of the chemical, biological and radiological incidents in the UK in recent years.

Dr Gent's team was mobilised in March of this year when Sergei Skripal and his daughter Yulia Skripal were poisoned in Salisbury, England, with a Novichok nerve agent.

After three weeks in a critical condition, Yulia regained consciousness and was able to speak. Sergei was also in a critical condition until he regained consciousness one month after the attack. Both wer discharged from hospital.

A police officer was also taken into intensive care after being contaminated when he went to Sergei Skripal's house.

In June a similar poisoning of two British nationals in Amesbury, seven miles from Salisbury, involved the same nerve agent.A man found the nerve agent in a perfume bottle and gave it to a woman who sprayed it on her wrist.The woman, Dawn Sturgess, fell ill within 15 minutes and died on 8 July, but the man who also came into contact with the poison survived.

A spokesman for Bolton School said: "Dr Gent praised the education he received at Bolton School and his former teachers, saying that in his work he still regularly uses the basic principles of biology, chemistry and physics which he learnt here and urged any aspiring medics to study physics, as he believes an understanding of this is a good basis for any medical career.

"He went on to give an enthralling account of his role in the Salisbury and Amesbury incidents, describing how a multi-agency response is coordinated when a major incident such as this is declared. He explained what a nerve agent actually is, how they work and what the signs and symptoms of nerve agent exposure are, as well as giving details of how to treat the patients."