In a Hardtalk Extra interview broadcast on Friday 1 April, Gavin Esler spoke to the pioneering British documentary film-maker Nick Broomfield.
Why are documentaries now enjoying box office success?
Documentary films are doing better than ever before at the box office.
A new wave of confrontational directors is bringing controversial subjects to a mainstream audience.
Nick Broomfield is a pioneer of this movement, a veteran director whose films on popular icons such as Kurt Cobain, Heidi Fleiss and serial killer Aileen Wuornos have earned numerous awards.
He explains why he thinks the documentary genre has become so popular.
HARDtalk Extra can be seen on Fridays on BBC World at 04:30 GMT, 11:30 GMT, 15:30 GMT, 19:30 GMT and 00:30 GMT.
It can also be seen on BBC News 24 at 04:30 and 23:30