You need to make a distinction between:

common law : a law common to all, lex loci aka law of the place, oral tradition based on customs, morals & ethics

Common Law : or british common law, not always friend of the people, plenty of atrocities committed under it, sometimes case law based on previous precedents

The Common Law : a codified version of common law, often found in acts of parliament and constitutions, serving as alibi, give citizens subjects an impression of common law; sometimes criminal matters in civil law jurisdiction will be subject to The Common Law, due to lack of statutes and/or their regulations