Jack, I believe ALbert Pierrepoint (Chief Executioner for Great Britain) carried out most of the Scottish death sentences in the 20th Century.
Even he eventually decided that the death penalty was not the answer, and resigned his position.
His autobiography is extremely interesting but completely chilling in its descriptions of the actual procedure. It shows exactly why taking a person's life in cold blood on behalf of the State is an appalling act, no matter what their crime.

For what it's worth, my opinion is that Brady was a psychopath, incapable of empathetic feeling. He killed because it was 'interesting' and, like many psychopaths, he enjoyed the control it gave him. As long as he was safely contained for the rest of his life, he no longer represented a danger to the public.

It is expensive to keep people in prison, but cold-bloodedly snuffing out a criminal's life makes one no better than a psychopath in my view.