The document advised that archaeological remains are a finite and irreplaceable resource and that their presence should be a material consideration in applications for new development. It accepted that development will affect archaeological deposits and that this effect must be mitigated. PPG 16 stressed the importance of the evaluation of a site for its archaeological potential in advance of development in order to inform future management decisions. This evaluation may involve non intrusive methods such as a desk-based study or archaeological geophysics and/or a more direct method such as trial trenching.