Cecilia Berdichevsky, Clementina expert (1961)en.wikipedia.org
It's odd that the English page contains much more information than the Spanish one [1]. There is even a book about the history of computer science in Argentina: <https://eudeba.com.ar/productos/de-clementina-al-siglo-xxi/> (in Spanish).
Clementina!
I don't know if this is apocryphal or not but that machine was supposedly named Clementina because it could 'play' part of "Oh my Darling, Clementine".
Found this cool video doing a little sampling but I have yet to find a sample of a Ferranti Mercury playing the tune. https://youtu.be/CiEw5kmRvvs?t=45
Edit: Here are some engineers playing games with 'her': https://toobnix.org/w/3doJWfhE3H1D5oVg2DYQQJ