Economist Thomas Piketty: Inequality 'becoming too extreme'

A new book on economics that highlights the gap between rich and poor has been rising in popularity.

Capital in the Twenty-First Century says that while inequality reduced in the 20th Century, it is now rising - a situation which the French author thinks is hugely dangerous.

Thomas Piketty told Newsnight's Jeremy Paxman that equality matters because "democratic institutions cannot work properly if inequity becomes too extreme".