Russian spy: What are nerve agents and what do they do?
[ad_1] Image copyright Reuters Image caption Officials in protective suits examine the area where Mr Skripal and his daughter were found Police say a nerve agent was used in an attempt to murder the Russian former spy Sergei Skripal and his daughter, Yulia, in Salisbury, Wiltshire. The pair are critically ill, along with a police officer who was among the first to attend the scene. But what are nerve agents