[Rich]

If it worked as a deterrent it would be satisfying.

Anyway, I think we may be straying from the point here, Jacob's punishments aren't intended to stop homicidal maniacs, they'll kill/rape people anyway.
Jacobs punishments are to stop the immoral, lawless scum that plague Britain from breeding and producing further cunts that will surely bring about our ultimate demise.

Hell, they probably wouldn't stop people from commiting crimes, but it would stop them from breeding, reducing the number of similar cunts, thus, these offenders are slowly wiped out, producing a utopian society.

PS: The castration doesn't mean they can't have children, if I remember correctly. Jacob was willing to take samples of the offenders sex cells, so if they ever became moral members of society, they could raise their own biological children.