Will Self believes we are reaching a state of 'peak envy'.

'Is it any surprise,' Will writes, 'that in this, arguably the second century of self, when for the most part humans see nothing around them but images of those better off than themselves, envy should be quite so epidemic: a greenish toxin - the very mustard gas of modernity.'

Producer: Adele Armstrong Sound: Peter Bosher Production coordinator: Gemma Ashman Editor: Richard Fenton-Smith