What is a Written Scheme of Investigation?

A Written Scheme of Investigation (WSI) is an important planning document usually required by Planning Authorities as part of a pre-application process or as part of an archaeological planning condition. The WSI outlines the proposed archaeological works required to satisfy a particular planning condition.

A WSI may be required on all manner of development sites, in particular those which may hold a known archaeological or historic interest or a potential for archaeological remains. In addition, if a site contains a building of historic interest a recording exercise may be required prior to demolition of or alterations to that building.

The methodology that is required to satisfy an archaeological planning condition must be agreed with the Local Planning Authority or their archaeological advisor, after which the WSI can be produced accordingly to provide a framework for archaeological works.

Why do I need a WSI?

The WSI is required to ensure that all parties agree to the archaeological methodology in advance and that work can be undertaken in accordance with the WSI under the supervision of the Local Planning Authority.

Many authorities will use standard archaeological planning condition wording which they will use for every site that requires such a condition. For example:

No development shall be carried out at the site until a Written Scheme of Investigation has been submitted to and approved by the Local Authority in writing.

As mentioned above, the WSI outlines the methodology for the proposed archaeological works – i.e. what are we initially going to do in order to satisfy the archaeological planning condition. To fully discharge the condition, those works would then need to be undertaken, as well as any subsequent archaeological works that may arise as a result of initial works.

What is included within the WSI?

Given that there are various types of archaeological work that could be outlined in a WSI, there are also various forms which a WSI may take. However, as a minimum, you should normally expect to see the following included within the document:

  • Non-technical summary
  • Site details, including location plan, grid reference
  • Plan of proposed works if applicable
  • Introduction including project and planning background
  • Site geological and topographical information
  • General archaeological and historical background for the site and immediate area
  • Aims and objectives of the works
  • Fieldwork methodology
  • Post-fieldwork methodology and reporting
  • Archive storage and curation of any finds (usually a local museum)
  • Copyright details
  • Quality and health & safety standards
  • References.

How long does it take to produce a WSI?

A WSI can usually be produced in 5-10 working days and would then be subject to agreement with the Local Planning Authority. Only once the WSI has been approved by the Authority or their archaeological advisor can archaeological works begin. 

WSIs prepared and/or approved by our team will adhere to the specifics of the project brief and comply with any relevant standards and regulations set by the Local Authority or industry bodies such as the Chartered Institute for Archaeologists (CIfA).

Find out more


Matthew Smith

Senior Director - Heritage T: + 44 7834345167 Email
London - Farringdon Street | UK

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