Who can carry out an archaeological field evaluation

Archaeological field evaluation secured by a planning condition has to be carried out under a written scheme of investigation approved by the local planning authority, and the practical answer to who can carry out an archaeological evaluation is an organisation accredited by the Chartered Institute for Archaeologists, with named staff whose individual accreditation matches the role they are doing. Councils rarely spell that out in the condition. They spell it out in the brief, and the brief comes from the county or borough archaeological advisor rather than from the planning officer.

What a written scheme of investigation does

The written scheme of investigation, usually abbreviated to WSI, is the method statement for the archaeological work. It sets out the aims, the techniques, the sampling strategy, the staffing, the recording system, the specialist arrangements, the health and safety approach, the reporting timetable and the arrangements for the archive.

Most archaeological conditions have the same two-stage structure. No development before a WSI has been submitted to and approved in writing by the authority, then no development other than in accordance with the approved WSI. That means two separate approvals in practice, and the second one is where programmes slip, because the fieldwork results have to be reported and accepted before the next stage is agreed.

The document is approved by the local planning authority, acting on the advice of its archaeological advisor. That advisor is frequently employed by the county council or by a shared service, not by the district that issued the permission, and their comments carry decisive weight on technical content even though the formal decision stays with the planning authority.

Who writes the WSI matters. It should be written by the organisation that will do the work, because a scheme written by a consultant and handed to a contractor who had no part in it tends to produce change control problems on site. Where a client wants independent oversight, appoint a separate archaeological consultant to review the WSI and monitor the fieldwork, and say so in the document.

Accreditation of organisations and individuals

Two layers of accreditation exist and they do different jobs.

The Registered Organisation scheme operates at corporate level. A registered organisation has been inspected against the Institute's standards, holds a quality management system, and is accountable through a complaints and disciplinary route. Most county archaeologists expect the fieldwork body to be registered, and some briefs say so expressly.

Individual accreditation operates at the level of the person. The grades run from Practitioner through Associate to Member, each tied to a level of competence and responsibility, and the Institute publishes a competence matrix behind them. For an evaluation the relevant question is who the project manager and the site supervisor are and what grade they hold, not what grade the organisation's director holds.

Three checks before appointment:

• Confirm the organisation's registration is current, and check it directly rather than taking a logo on a proposal at face value.
• Ask for the named project manager and site supervisor, their accreditation grade, and their experience of the period and site type in question.
• Ask who the specialists are for finds, environmental samples and conservation, because a thin specialist network produces thin reports.

The same pattern applies across heritage disciplines, and the structure of individual competence requirements for historic building recording levels is a useful comparison when assessing a mixed heritage team.

The county archaeologist's role in setting the brief

The brief defines the scope, and the scope defines the cost. It is written or approved by the archaeological advisor and it usually states the area to be evaluated, the technique, the sampling level, the standards to be followed, the reporting requirements and the archive destination.

Engage with the brief before it is finalised. A brief issued without site constraints in mind may specify trenching across an area occupied by a live gas main, or require work in a standing crop. Those issues cost far less to resolve at brief stage than by variation on site.

Where the desk-based evidence is thin, press for the evaluation to be designed off the back of an archaeological desk-based assessment rather than a generic percentage. An assessment that identifies the historic environment record entries, the cropmark evidence, the historic mapping and the geology gives the advisor something to target and usually reduces the area that needs opening.

Reporting, archiving and publication

The obligation does not end with the fieldwork, and clients routinely underestimate the tail.

The Framework expects developers to record and advance understanding of the significance of any heritage asset to be lost, and to make that evidence publicly accessible. Archive deposition is where that obligation lands, and museums increasingly charge for accepting material and apply selection policies. Ask at quotation stage which repository will take the archive, whether it is accepting deposits, and what the charge is. A refused archive leaves a condition undischarged years after the development is finished.

Publication obligations are proportionate to the results. A negative evaluation needs a report and an index entry. A site producing a Romano-British farmstead needs more, and the cost of that analysis and publication should be identified as a contingency rather than discovered later.

Checking the brief before you accept a quotation

Quotations for the same brief vary widely, and the variation usually sits in what has been excluded.

1. Confirm the sampling level and the area, expressed in both percentage and square metres.
2. Check whether machine hire, spoil handling and reinstatement are included.
3. Check whether the price includes utility searches and scanning before excavation.
4. Check the post-excavation allowance, the specialist allowance and whether publication is included or excluded.
5. Check the archive deposition charge, and which repository is assumed.
6. Check what happens if significant remains are found, and whether mitigation excavation is priced as a provisional sum or excluded entirely.
7. Check the reporting timetable in weeks, because an unstated timetable becomes a long one.

Item six separates realistic quotations from optimistic ones. An evaluation is a sampling exercise, and the point of it is to find out whether further work is needed. A quotation with no provision for that outcome is a quotation for half the job.

Programme risk from an evaluation condition

Archaeological conditions are among the most common causes of delay between permission and start on site.

Build the sequence into the programme honestly: brief agreed, WSI written, WSI approved, fieldwork mobilised, fieldwork done, report produced, report accepted, mitigation strategy agreed if needed, mitigation carried out, final report and archive. Each of those steps involves a third party, and several involve the authority's archaeological advisor, who is typically covering a whole county.

Three practical mitigations are available. Do the evaluation before determination where the desk-based assessment suggests real potential, so the planning decision is informed and the condition is narrower. Agree a phasing arrangement so that evaluation of later phases does not hold up the first. And appoint early, because archaeological contractors book out in the spring and a site that needs trenching in February will be working in difficult ground.

For the written documents, an archaeological field evaluation draft gives the structure and the policy framing. Councils normally expect a suitably qualified author, professional review is strongly advised, and the fieldwork itself must be done by an accredited organisation. Where you need a reviewer with the right accreditation, the professional directory is the route to one.

See which heritage documents a site needs by browsing the report categories and starting a draft.

This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval. For specialist technical reports, qualified professional input may be required.