Is Magna Carta the foundation of modern English law?
Short answerNot by itself. English law passed through many transformations, especially across the interregnum, even when Commonwealth measures were later reissued as royal acts.
NotesEnglish constitutional law did not develop in an uninterrupted line from one medieval charter. English law before the interregnum differed from the system that emerged afterward. Although Restoration theory repealed the acts of the kingless period, many of their practical measures returned in royal form. Magna Carta remained historically important, but it cannot by itself explain that institutional development.