1st November 2006: Alexander Litvinenko is brazenly poisoned in central London. Luke Harding's investigation into the death of Alexander Litvinenko, A Very Expensive Poison, may also help us shed light on the poisoning of Sergei Skripal and his daughter in Salisbury.

The shocking true story of the Litvinenko poisoning, told by the author of The Snowden Files and Wikileaks.