London's happiness revealed in social media exhibition

There has been an explosion in the amount of digital information people are producing.

In 2009 we generated the same amount of data as we did in the entire history of humanity up until that point.

A new exhibition at Somerset House in central London is looking at how posts on social media are used to reveal which London boroughs are happiest in real time.

It also shows how selfies taken by people in the capital differ from elsewhere around the world.

Alice Salfield reports.