Sir Joseph Rotblat lived in a flat on the Square in the mid twentieth century, while working at Liverpool University. Amid a very interesting life, Polish-born Rotblat worked on the Manhatten Project, which strove to develop the first atomic bombs. Better than this though, he quit the project because of his moral concerns over the work, one of the few to do so. A founder member of CND and a Fellow of the Royal Society, he was awarded the Nobel Prize for Peace in 1995, for his work towards nuclear disarmament with the Pugwash Conferences. This is aside from his own contributions to science and nuclear physics, and his own fascinating journey.
"He can have few rivals in the courage and integrity and complete self-abnegation with which he has given up his own career (in which, however, he still remains eminent) to devote himself to combating the nuclear peril as well as other, allied evils."
One of the good ones. I'm afraid you'll have to wait for volume two to hear more about his time in the Square though!