Magna Carta - a Common Law document - was originally signed in 1215, a contract between the knights, barons, clergy, townspeople and the King. Magna Carta affirmed the right of the People to such things as trial by jury, and protection from excessive fines.
In 1297 the Model Parliament confirmed Magna Carta in statute law. Much of this statute has since been repealed. It should be noted that while Parliament can repeal or amend any Act of Parliament (statute), Parliament was not a party to the original Common Law contract, and cannot, therefore, amend or repeal it lawfully, and thus its original provisions remain intact.