I believe in capital punishment for certain crimes - the worst kind of serial killers, rapists and child rapists should really be executed.
If you commit those kind of crimes, you forfeit your right to live.
Of course, people who leave Islam or mock Muhammad should not be killed, or punished by the state in any way.
I believe we in the UK should have capital punishment on the books even if we wouldn't use it - much in the same way US authorities often drop the death penalty in exchange for an admittance of guilt.