A language developed in the early 1960s at the Universities of Cambridge and London in the UK. Although it never came into general use, CPL is noteworthy for the fact that it anticipated many of the concepts that are now regarded as characterizing modern ‘advanced’ languages, notably the control structures of structured programming and the reference concept that formed a major feature of Algol 68. CPL was the direct precursor of BCPL and thus an ancestor of C.