Kerr Avon was one of the best antihero characters in science fiction. Darrow was sublime in the role.
I have never understood why it should be necessary to become irrational in order to prove that you care. Or indeed why it should be necessary to prove it at all.
Always shield the top of your gun with your left hand while aiming it. Remember the man who produced the most acerbic remarks in the galaxy, the only man who could take a show named after a charismatic character and keep it going without that character. Always destined to be the last man standing.
(I just now finished watching the incredible finale of Blake's 7, and came back to post this. Capable, compelling, captivating, and completely unflappable right up to the last instant of the show, Kerr Avon is one of the most memorable characters in sci-fi.)