I also read the auto biography of the 'number two' hangman, but can't remember whether it was Harry Allen or Robert Stewart. However, what I can remember is the moaning about how Pierrepoint had killed (pun intended) his career. Apparently, whilst assisting Pierrepoint as number two, he commented on the large penis of the freshly executed man. You can just imagine the collective cringe as he pointed to a corpse, exclaiming, 'look at the size of that cock!'.
You wouldn't want to have a pint with him! As a final non-sequitur, my parents brought me up to believe that the home office was deluged with letters offering to be hangman, in order to display the depravity of humanity. This is a myth that QI exposed.