One of the interesting things about writing is you often end up researching what may seem to be random topics. Sometimes the research done doesn't make it into the final draft, but it's always a weird and wonderful journey.
Doing some research for a character who may (or may not) have Soviet ties lead me to investigate the rise of the Communist movement during the Thirties among British university students (especially those at Trinity and King's Colleges at Cambridge University).
The Cambridge Five were the most infamous of the Cambridge students infatuated with Marxism. They became passionate believers in during their student years in the Thirties and ultimately became spies for Stalin, passing British state secrets to Russia.
Because of their education and high social class, they were able to not only keep their cover, but achieve prominent careers with MI-5 (oh, the irony), the BBC and the Royal Family.
For those who'd prefer not to wade through all the reading, Cambridge Spies (2003) is a two-disk multi-part series dramatizing the lives of the five from 1934 through the Fifties. It was written by Peter Moffat and directed by Tim Fywell and produced and first shown on the BBC.