If you're interested in trying out BCPL on your own machine the inventor of the language, Martin Richards, maintains a working environment/compiler[0]. I've gotten it up and running on both Ubuntu and OS X. The readme is structured in a way that makes it kinda hard to follow so I wrote down some instructions[1] for my future self after I figured it out.

C was my first programming language and several years ago I became acquainted with ALGOL 68. I'd never seen BCPL before a few months ago. It's rather interesting how, from the perspective of someone born well after its creation, it is very clearly the link between the ALGOL family and C. I'm sure that's rather obvious to programmers who were around in the mid to late 60's but for me personally it was a lot like discovering a missing link.

[0]: http://www.cl.cam.ac.uk/~mr10/BCPL.html

[1]: https://gist.github.com/seaneshbaugh/e09abd748ccc07c5463f253...