http://iclces.uk/index.html The ICL Computers Education In Schools (CES) project.
https://closingbraces.net/2010/01/18/in-memory-of-cesil/ Some good CESIL links in the comments.
http://stevenicklin.com/downloads/cesil.awk CESIL in AWK, GPL licensed, posted by author on rasberry pi forum.
and: vintage BASIC including the source to the games for “BASIC computer games” by
Mindstorms-Children-Computers-Powerful-Ideas Worth reading the Amazon.com reviews aswell
ICL International Computers Limited:
http://www.icl1900.co.uk/index.html All about the 1900 series mainframe computer
https://www.retrobrewcomputers.org/doku.php Build your own computer. Many good people – many good computers to build. Group formally known as N8VEM.