This song is based on the true story of Chris Craig and Derek Bentley. It is used to show the tragic irony and fundamental flaws of the death sentence.

Brief summary of the case:
Derek Bentley and Chris Craig committed a crime together and were armed and on the run when the police caught up to them. Bentley was caught by the leg, but broke free, after which a police officer allegedly told Craig to “Hand over the gun, lad”, then Bentley called out “Let him have it, Chris”. Bentley was re-caught and restrained, and soon after Craig shot and killed a policeman, before being caught himself.

In the trial the pair were found guilty of the murder of the policeman Sydney Miles. Since Bentley was 19 he was sentenced to the death penalty, while Craig was only 16, so he was sentenced to prison.

The case was controversial because:
-Craig fired the weapon that killed Miles, but Bentley was sentenced to death
-The phrase “Let him have it Chris” could have meant literally hand over the gun, instead of the understood meaning of “Shoot him Chris” (used in the similar way as in Old Gangster films.
-other reasons (See Wikipedia Link)

Bentley was fully pardoned and his charge of murder quashed in 1998, he would have been 65 years old, were it not for his untimely death.

https://en.wikipedia.org/wiki/Derek_Bentley_case