Stephenson:Neal:Quicksilver:343:Jack Ketch (The Shabby Sheik)

From the Quicksilver Metaweb.

Jack Ketch is the default nickname for all English executioners. The name in this context is likely a slight anachronism, as the original namesake Jack Ketch isn't recorded in the position until 1678, remaining the Public Hangman of London until 1686. He remains renowned in the annals of capital punishment for being profoundly bad at his profession. Sir Charles Lyttelton reports that in the (ultimately successful) attempt to behead Lord William Russell, Ketch "gave him 3 blows, besides sawing wth ye ax, before he cut his head of." Even worse was the final end of the Duke of Monmouth after Sedgemoor, who took five blows and some improvised knife-work before his caput was finally kaput.