Queen v Dudley & Stephens

Four men from an English ship are trapped on a boat in the sea after a storm. After a few days, they ran out of their provisions. They go on without food or water for a week, after which the captain of the ship, Thomas Dudley, proposes to kill one of the four men by drawing lots so that the rest of them can feed on his body to sustain their life. Edward Stephens agrees to the proposal, but Ned Brooks refuses, and the cabin boy is not consulted. Some days later, Dudley and Stephens decided to kill the cabin boy stating that he was ill anyway. Later all three of them feed on his flesh.

The two defendants, Dudley and Stephens, are charged with murder.

The question that arose here was (i) whether 'necessity' can be claimed as a defense for murder?, and (ii) whether killing another person to save one's own life be termed as self-defense in this case?