The Ancient Monuments and Archaeological Areas Act 1979 or AMAAA was a law passed by the UK government, the latest in a series of Ancient Monument Acts legislating to protect the archaeological heritage of England & Wales and Scotland. Northern Ireland has its own legislation.
Section 61(12) defines sites that warrant protection due to their being of national importance as 'ancient monuments'. These can be either Scheduled Ancient Monuments or "any other monument which in the opinion of the Secretary of State is of public interest by reason of the historic, architectural, traditional, artistic or archaeological interest attaching to it".
A monument is defined as:
Damage to an ancient monument is a criminal offence and any works taking place within one require Scheduled Monument Consent from the Secretary of State.
The Act also provides for taking monuments into the care of the Secretary of State – the concept of 'guardianship' where a monument remains in private ownership but the monument is cared for and (usually) opened to the public by the relevant national heritage body.
The Act (in Part II) also introduced the concept of Areas of Archaeological Importance, city centres of historic significance which receive limited further protection by forcing developers to permit archaeological access prior to building work starting. As of 2004 only five city centres, all in England, have been designated AAIs (Canterbury, Chester, Exeter, Hereford and York). Part II of the Act was never commenced in Scotland.