How to kill a human being.

Michael Portillo, who has long debated the death penalty as a method of punishment, searches for a humane way of killing. 55 countries execute their criminals and here Portillo attempts to understand what it feels like to be executed, frequently undergoing experiments which push his body to the brink of death. Portillo travels to America and meets Jay Chapman, the man who invented the lethal injection which is currently thought to be potentially inhumane. Other methods of execution looked at include the gas chamber, hanging and the electric chair. Hanging is used regularly in non-Western countries but in order for it to be humane the height of the drop must be measured very precisely. Portillo witnesses a simulated electric shock on a pig which is described as tantamount to torture and he undergoes exposure to CS gas in order to see if it is possible for a prisoner to remain calm when executed by cyanide gas. Scientists regularly have to perform euthanasia on lab animals and they believe hypoxia can be induced without suffering. To put this to the test Portillo spends time in a human centrifuge and a high altitude chamber. The hypoxia induced in the high altitude chamber appears to be the most humane form of execution; finally Portillo meets Mohan Raj from Bristol University who is using nitrogen to produce a painless euphoric hypoxia to kill farm animals.