Strachey was also the lead programmer behind the programming language CPL, the great-grandfather of C (via BCPL and B). CPL was too ambitious and was never completely implemented - it tried to do everything; a bit like Perl 6 really.
The overview paper:http://comjnl.oxfordjournals.org/cgi/content/abstract/6/2/134 is quite interesting; sadly it is now behind a pay-wall. There are some features of the language, such as type inference, which have not become common until recently. It also has some obvious poor decisions with hindsight - the same character starts and ends blocks; all lower case letters are single-character variable names; multiple-character variable names must be capitalised (this is done to allow implicit multiplication, ie, xyz=x*y*z). I suspect it could be implemented without huge difficulty with modern tools. Unfortunately, the full definition was never published, and only exists in a few copies of 'The CPL Working papers' archived in university libraries. Perhaps one day google will scan it.
Link to Original Source