PPG 16British Government to advise local planning authorities on the treatment of archaeology within the planning process. It was introduced in November 1990 following public outcry after a number of high profile scandals such as the threatened destruction of the Rose Theatre in London by developers.
The document advises that archaeological remains are a finite and irreplaceable resource and that their presence should be a a material consideration in applications for new development. PPG 16 stresses the importance of the evaluation of a site for its archaeological potential in advance of development. This evaluation may involve non intrusive methods such as a desk-based study or geophysical survey and/or a more direct method such as trial trenching.
Following the results of initial evaluation, PPG16 offers two solutions for preserving any significant archaeological deposits on a development site. The first, and explicitly preferred, method involves preservation in situ whereby the archaeology is left untouched beneath a new development through methods such as adaptation of foundation design and architectural layout of the proposed new development, or by raising the level of the development with made ground so that its foundations do not reach the archaeological horizon.
If preservation in situ is not feasible then PPG 16 permits preservation by record. This involves archaeological fieldwork to excavate and record finds and features (thereby destroying them). This may involve a full strip map and sample excavation, further trenching or an archaeological watching brief which involves an archaeologist monitoring groundworks for the new development and recording any finds or features revealed.
All forms of archaeological investigation undertaken through PPG 16 are funded by the developer through an extension of the Polluter Pays principle. The work is usually undertaken to satisfy a planning condition placed on an application for development. A developer tenders for the work to be done and chooses an archaeological organisation to retain. The work is monitored by a curator, normally the County Archaeologist, who is nominated by the local planning authority as an advisor and who also recommends planning conditions to be placed on new development applications. Following submission of a satisfactory site report, the curator will usually advise discharge of the condition so that development can continue.
Curators maintain a Sites and Monuments Record or SMR, a database of known archaeological sites which is often used to inform decisions on archaeological potential.
PPG 16 has resulted in an explosion in archaeological fieldwork in the UK. Developer funding has led to dozens of archaeological organisations competing for work along with archaeological consultants working for developers to oversee projects. This has contributed to the growing professionalisation of archaeology from its more ad hoc earlier incarnation as Rescue Archaeology. Also, a wider variety of archaeological methods are now employed including surveys of large areas for the puposes of Historic Landscape Characterisation, deposit models and the production of regional archaeological research agendas.
Critics of PPG 16 argue that the commercialisation of UK archaeology has resulted in more work of lower quality being undertaken; there is a certainly a liability of unpublished site reports and homeless site archives awaiting resolution. The competition for work amongst archaeologists, and the fact that the developers funding them have no real use for their final product, also tends to drive prices down meaning that wages and conditions for archaeologists in the UK are generally far below the national average.
Theoretically, the philospohical approach of PPG 16 is strongly processualist, especially following the publication of the de facto guidance manual for UK developer-led archaeology, English Heritage's Management of Archaeological Projects (1991) , popularly known as MAP 2. This stresses the importance of evaluation, documentation and decision-making at each stage of a project based on empirical evidence and valid hypotheses.
A similar, though less stringent, guideline to PPg 16 exists for historic buildings and standing archaeology called PPG 15. As of 2004 both documents are proposed to be combined into a single piece of guidance called a Planning Policy Statement