<P> European Community Law </P> <P> The European Union is special example of international law . European nations that join the EU thereby adopt all EC Law to date (the acquis communautaire), namely: treaty provisions, regulations, directives, decisions, and precedents . Member States become subject to "Brussels" and to the binding precedent decisions of the Court of Justice of the European Union (or CJEU) in Luxembourg . However, Brussels may only act and legislate in accordance with the EU treaties, and the CJEU's supremacy applies only in matters of EU law . </P> <P> Legislation Legislation is the prime source of law . and consists in the declaration of legal rules by a competent authority . Legislation can have many purposes: to regulate, to authorize, to enable, to proscribe, to provide funds, to sanction, to grant, to declare or to restrict . A parliamentary legislature frames new laws, such as Acts of Parliament, and amends or repeals old laws . The legislature may delegate law - making powers to lower bodies . In the UK, such delegated legislation includes Statutory Instruments, Orders in Council, & Bye - laws . Delegated legislation may be open to challenge for irregularity of process; and the legislature usually has the right to withdraw delegated powers if it sees fit . </P> <P> Most legislatures have their powers restricted by the nation's Constitution, and Montesquieu's theory of the separation of powers typically restricts a legislature's powers to legislation . Although the legislature has the power to legislate, it is the courts who have the power to interpret statutes, treaties and regulations . Similarly, although parliaments have the power to legislate, it is usually the executive who decides on the legislative programme . The procedure is usually that a bill is introduced to Parliament, and after the required number of readings, committee stages and amendments, the bill gains approval and becomes an Act . </P>

Advantages of act of parliament as a source of law