Matthew Parris's guest this week is the epidemiologst Precious Lunga, who nominates for Great Life status that of the Kenyan environmental activist Wangari Muta Maathai.

In the course of her life, Professor Maathai made a huge contribution to re-establishing environmental integrity to Kenya by working with the women who lived there. She founded the Green Belt Movement and became a politician. In 2004 she was awarded the Nobel Peace Prize. The expert witness is Maggie Baxter from the Green Belt Movement.

First broadcast on BBC Radio 4 in 2015.