In the first of two programmes he looks back to the first attempts to ban the use of chemical weapons at the end of the 19th century. Heavily defeated in the Crimea, Russia succeeded in getting unanimous agreement at the 1899 Hague Convention that poison and poison weapons should be banned from warfare. But chemicals such as chlorine, phosgene and mustard gas were heavily used in the First World War by both sides. More substances were developed in the 1930s and 1940s but weren’t used in the battlefield in World War 2. Andrea Sella tells the stories of the chemists behind these developments. Picture: GB Army soldiers train for biological and chemical warfare, Credit: BBC

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“What did the council decide on item 42?” — answered with the speaker and the moment.