In the United Kingdom, a scheduled monument is a 'nationally important' archaeological site or historic building, given protection against unauthorised change. The protection given to scheduled monuments is separate from the Town and Country Planning system. Scheduled Monuments are defined in the Ancient Monuments and Archaeological Areas Act 1979. In England, Wales and Scotland they are often referred to as a scheduled ancient monument - although the Act defines only ancient monument and scheduled monument. In Northern Ireland they are designated under separate legislation and are referred to as a scheduled historic monument (for those in private ownership) or a monument in state care (for those in public ownership).
Of the tens of thousands of scheduled monuments in the UK, most are inconspicuous archeological sites, but some are large ruins and others intact buildings which remain in use.
Occasionally scheduled monuments are also designated as listed buildings (eg. Dunblane Cathedral), although the latter designation is generally only applied to buildings and structures which are, or could be, in modern day-to-day use. Where a monument is both scheduled and listed, many provisions of the listing legislation are disapplied (for example those relating to Building Preservation Notices).
In England the Department for Culture, Media and Sport keeps a register, or schedule, of nationally important sites which receive state protection; this now includes over 31,000 sites. This process was first devolved to Scotland and Wales in the 1970s and is now operated there by the Scottish Government and the Welsh Assembly Government. The three government bodies with responsibility for archaeology and the historic environment in Britain are: English Heritage in England, Cadw in Wales, Historic Scotland in Scotland. The Northern Irish system is governed by separate legislation, and is operated by the Northern Ireland Environment Agency in Northern Ireland.
A long list of criteria is used to decide whether an ancient monument should be scheduled. Scheduling affords greater protection as it becomes illegal to undertake a great range of works within a designated area, without 'scheduled monument consent'. The Scottish criteria were revised between 2006 and 2008.
To be eligible for scheduling, a monument must be demonstrably of (in the terms of the 1979 Act) 'national importance'. Non-statutory criteria are provided to guide the assessment. In England these are:
There is no appeal against the scheduling process and adding a monument to the schedule may be a process requiring a great deal of research and consideration. The process can be accelerated for sites under threat, however. In England, English Heritage gathers information on a site, defines a boundary around it and advises the Secretary of State for Culture, Media and Sport of its eligibility for inclusion on the schedule. In Scotland and Wales Historic Scotland and Cadw are part of central government and act on behalf of the relevant ministers.
Protection can be given by taking the monument into state ownership or placing it under guardianship, the latter meaning that the owner retains possession, while the appropriate national heritage body maintains it and (usually) opens it to the public. Field Monument Wardens monitor sites to check their condition and to report on damage etc. Wider areas can be protected by designating their locations as Areas of Archaeological Importance. As of 2004 only five city centres, all in England, have been designated AAIs (Canterbury, Chester, Exeter, Hereford and York). This part of the 1979 Act was never brought into effect in Scotland.
Damage to a scheduled monument is a criminal offence and any works taking place within one require Scheduled Monument Consent from the Secretary of State or her devolved equivalent. Despite perceptions to the contrary, only a very small proportion of applications for SMC is refused. In Scotland in the 10 years 1995–2005, out of 2156 applications, only 16 were refused. Development close to a scheduled monument which might damage its setting is a material consideration in the planning system.
The Scheduling system is criticised by some as being cumbersome. It also has a limited definition of what constitutes a monument. Features such as ritual landscapes, battlefields and flint scatters are difficult to schedule. Scheduling is not usually applied to underwater sites, although three maritime sites have been designated as scheduled ancient monuments. In England radical change has been proposed, which will see a single 'register' created that includes scheduled monuments and listed buildings.