One Planet examines the ethical and practical implications if people begin to live for 200 years and beyond.
David Eagleman is an American neuroscientist whose book: Sum: Forty Tales from the Afterlives, imagines a world where everyone lives for centuries, even as long as beyond 300 years.
He has written a funeral speech, from an imagined future, in which a relative has died prematurely at the age of just 122 years.
One Planet presenter, Mike Williams, visited a day centre for elderly people in south London.
First broadcast 24 June 2010