The major sources are (i) case law, (ii) legislation and (iii) European Community law.
Case law
A statement of the law made by a judge in deciding a case establishes a precedent and will be relevant for future similar disputes depending on the status of the court. The doctrine of binding precedent depends on: (i) a court hierarchy and (ii) accurate and efficient law reporting, which were only fully achieved by the end of the nineteenth century.
The binding element in legal decisions.
Reports detail facts, names of parties, a statement of the law forming the basis of the decision and the judgement. Only the statement of law forming the basis of the decision is binding. Cases may contain other statements of the law. The binding statement is the ratio decidendi (the reason for the decision). Other statements are merely persuasive and are called an obiter dictum (a statement of law made by the way).
A ratio decidendi is a statement of law applied to the legal problems raised by the material facts of the case as identified by the court upon which the decision is based. There are two types of obiter dictum: (i) a statement of law based upon facts which were either not found to exist or, if found, were not found to be material; or (ii) a statement of law which, although based on material facts of the case as identified by the court, does not form the basis of the decision. The first is a statement of law based upon a hypothesis. The second is a dissenting judgement in a court where there is majority decision.
Precedents which are not binding.
These include: (i) persuasive precedents; (ii) precedents which have been overruled; (iii) precedents which have been distinguished; and (iv) per incuriam precedents.
Equitable rights and remedies are discretionary, not claimable 'as of right' as with common law rights and remedies. Equity looks beyond legal formalities and enforces the intentions of the parties as in the recognition of leases and mortgages lacking the formalities required by the common law. Equity recognises agreements to create leases or mortgages as creating rights between the parties which can be specifically enforced by a decree requiring the drawing up of a formal lease or mortgage and developed a wider notion of fraud restraining people from doing something which would be inequitable; that is, unfair although legal.
The main value of equity today is that judges use their equitable discretion to avoid the rigidity of the doctrine of binding precedent.
Legislation
Legislation, the major source of law, exists in two forms: direct legislation in the form of Acts of Parliament and delegated legislation, in the form of by-laws, statutory instruments andOrders in Council. Parliament has absolute legislative power through Acts of Parliament to revise substantive rules of law, consolidate existing enactments, codify the law, implement treaties and introduce social legislation. In principle, no statute can limit the legislative freedom of future parliaments but major limits on this sovereignty arise through Britain's membership of the European Community.
Delegated legislation is enacted by bodies authorised by Parliament. Delegated legislation must be within the powers (intra vires) of the body enacting it, otherwise it is ultra vires and illegal. By-laws are passed by local authorities and other authorised bodies. Statutory instruments are made by government departments under authority given by direct legislation and introduce detailed regulations under the principal Act. This speeds up the legislative process by enabling regulations to be made and altered quickly without placing them before Parliament. An Order in Council is an order promulgated by the government but through the Privy Council.