In British archaeology a Watching Brief is a method of preserving archaeological remains by record in the face of development threat. An archaeologist is employed by the developer to monitor the excavation of foundation and service trenches, landscaping and any other intrusive work. The developer undertaken to give the archaeologist sufficient time to identify and record and archaeological finds and features, however the arrangement is rarely satisfactory for either party.

It is often difficult to identify archaeological features in narrow foundation trenches and the potential delay to a project can also difficult for a developer to incorporate into a development programme. Prior evaluation through trial trenching can overcome these problems by having the archaeology examined and removed or preserved before groundworks commence.