Just a bit of clarification on early release:
All prisoners serving determinate sentences are released at the halfway stage, the remainder of their sentence being served on licence. This release is automatic and unconditional. In addition most of those serving between three months but less than four years are eligible for earlier release under “Home Detention Curfew” (there are exceptions for some offenders convicted of sexual offences). This provides for a further reduction of between 15 and 90 days. (This is the situation in England and Wales but I believe similar arrangements apply in Scotland).
“Not all sentences are reduced. In-law of my son's wife was given 9 years for murder (lesser sentence because it was classed as a domestic gone wrong). He served every day of the 9 years.”
The release at the half way point is only applicable to determinate sentences, maggiebee. Murder carries a mandatory sentence of Life, which is not a determinate sentence. It is an open ended sentence and the judge accompanies the sentence with a recommendation of the minimum period that must be served before parole is considered. This is the absolute minimum and no early release is available.