There is an Air Navigation Act - it establishes the CAA's powers to regulate aviation. The day to day business of giving legal force to the rules they propose is done by the Secretary of State for Transport putting the ANO through the system. Amendments are placed in the House of Commons library for a period (two weeks I think) and if no objections are raised it is passed. If any MP does object it has to be debated in Parliament which really puts a spanner in the timetable, so there is pressure on the guys at Gatwick (official title "the servants of the Authority") to get things right first time - legally speaking as opposed to operationally.
This system is how most of UK government works. If you go to
www.hmso.com you will find a section "Statutory Instruments", and you will see that there are literally hundreds of them!
I think that the fact I know this officially qualifies me as sad
