What makes a dystopian novel?

There's a new book out called The Wall by John Lanchester, a dystopian novel set in the near-ish future.

But what makes a dystopian novel? And why are we so fascinated with them?

The BBC's Arts editor Will Gompertz explains.

Produced by Emily Wolstencroft and Claudia Redmond

Will Gompertz reviews John Lanchester's dystopian novel The Wall