Life should mean life ?. Trouble is that full life terms for all would not distinguish between murders. The man who killed 20 on a shooting spree or who abducted, abused, and killed several chidren, would be treated the same as one who intended to cause really serious bodily harm with one heavy blow to the face, but who killed the victim, though he neither foresaw nor intended death.
That's why some (most, in fact, if I recall aright) murderers were spared the death penalty, obligatory for all murders; the Home Secretary distinguished between the various murders and murderers. What's more, those who were spared did not necessarily serve a full life term. Judges have the power now to make such a distinction with 'life' sentences.