In 1951 the league gained its first Cambridgeshire club with the admission of Cambridge United, and by 1955–56 the league was up to 20 clubs, of which five were reserve or 'A' teams.
I 1951 fik ligaen sit første hold fra Cambridgeshire, da Cambridge United blev optaget, og i 1955–56 nåede antallet af hold op på 20, hvoraf fem var reserve- eller 'A'-hold.