Sources of law & doctrine of precedent

LS.02 — Sources of Law & Doctrine of Precedent

Sources of law (hierarchy)

• Acts of Parliament (primary legislation) — supreme source. Courts apply them; they cannot strike them down (parliamentary sovereignty).
• Delegated/secondary legislation (SIs, byelaws, regulations) — made under enabling Act; can be challenged by judicial review for ultra vires.
• Case law (common law + equity) — judge-made; binding via precedent.
• Retained/assimilated EU law — see below.

Doctrine of precedent (stare decisis)

• Only the ratio decidendi (legal reason for the decision) binds. Obiter dicta are persuasive only.
• Vertical binding: lower courts bound by higher courts.
• Horizontal: Supreme Court can depart from its own decisions (Practice Statement 1966); Court of Appeal generally bound by itself, with the Young v Bristol Aeroplane [1944] exceptions (conflicting CA decisions, conflict with later SC/HL decision, per incuriam).
• Avoiding precedent: distinguishing (material facts differ), overruling (higher court), reversing (same case on appeal).
• Court hierarchy: Supreme Court → Court of Appeal → High Court → County/Crown/Magistrates.

Statutory interpretation

• Literal, golden, mischief rules; modern courts favour the purposive approach.
• Aids: intrinsic (long title, headings) and extrinsic (Hansard under Pepper v Hart [1993], dictionaries, Interpretation Act 1978).
• Rebuttable presumptions; rules of language (ejusdem generis, expressio unius).
• HRA 1998 s.3: read legislation compatibly with ECHR "so far as possible"; if impossible, s.4 declaration of incompatibility (does NOT strike down the Act).

EU / assimilated law (current)

• REUL Act 2023 renamed retained EU law to "assimilated law" and ended EU supremacy from 1 Jan 2024.
• Trap: REUL Act 2023 s.6 (new departure test + lower-court reference route) never came into force (commencement revoked by SI 2024/976). The EUWA 2018 s.6 framework still governs: Court of Appeal and Supreme Court may depart from assimilated case law on the own-precedent basis; lower courts/tribunals remain bound.

Common traps

• Precedent binds on the ratio, not the outcome or obiter.
• Court of Appeal is not free like the Supreme Court — Young exceptions only.
• Pepper v Hart is narrow (ambiguity + clear ministerial statement).
• s.4 HRA gives a declaration, never invalidation of primary legislation.
• Use "assimilated law", not "retained EU law", post-2024; do not cite the dead REUL s.6 test.