More than four billion people live in countries which retain the death penalty. Mike Williams asks why more than 50 countries around the world still execute certain criminals. What is the death penalty for and how is it carried out? He talks to a former American prison officer who presided over 33 executions in the US state of Ohio and asks whether he has any regrets. He also speaks to a Nigerian former death row prisoner who escaped the gallows with just seconds to spare. And he hears from a lawyer in Indonesia where two convicted Australian drug traffickers are awaiting execution.

Produced by Caroline Bayley

(Photo: The Texas death chamber in Huntsville, Texas. Credit to: Joe Raedle/Newsmakers)