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.