a statutory instrument
(a) made in the exercise of a legislative power conferred by or under an Act of Parliament, or
(b) for the contravention of which a penalty, fine or imprisonment is prescribed by or under an Act of Parliament,
and includes a rule, order or regulation governing the practice or procedure in any proceedings before a judicial or quasi-judicial body established by or under an Act of Parliament, and any instrument described as a regulation in any other Act of Parliament;