Written scheme of investigation: what the archaeologist needs
The written scheme is the document that turns an archaeology condition into a programme. Post-excavation and archive deposition are where the cost lands.
A written scheme of investigation is the document that converts an archaeological planning condition into a programme with dates, methods and costs. It is written by the archaeological contractor, approved by the local planning authority on the advice of its archaeological adviser, and it governs everything that follows, including the obligations that outlast the fieldwork.
Developers underestimate the tail. Fieldwork is visible and finite. Post-excavation assessment, specialist analysis, publication and archive deposition are none of those things, and on a site with good preservation they will cost more than the digging did.
Who writes the scheme and who approves it
The contractor writes it, you commission it, the authority approves it. The adviser is usually a county archaeologist, a borough archaeologist, or in London the Greater London Archaeological Advisory Service within Historic England.
Choose the contractor on the strength of the team rather than the line price, and check the position on registration with the Chartered Institute for Archaeologists. The written scheme will be judged against the institute's standards and guidance for the relevant type of work, whether that is evaluation, excavation, watching brief or building recording, and a contractor who works to those documents daily produces a scheme that gets approved first time.
One procedural point that saves a fortnight. Ask the authority who the approving officer is and send a draft for comment before the formal submission. Advisers will almost always mark up a draft, and a marked up draft is faster than a refused discharge application.
The brief issued by the county archaeologist
The brief comes first. It states the area to be investigated, the archaeological questions to be addressed, the methods expected, the standards to be applied and the monitoring arrangements. It is short, often two or three pages, and it is the specification the scheme has to answer.
Get it in writing before you ask for quotations, because contractors pricing against different assumptions produce numbers you cannot compare. If the authority has not issued a brief, ask for one, or ask the contractor to write the scheme against an agreed scope confirmed by the adviser by email.
Where an Archaeological Desk-Based Assessment was submitted with the application, the brief will usually build on its conclusions, and where an Archaeological Field Evaluation has already taken place the brief will be shaped by what was found.
Fieldwork methodology and the area covered
This is the bulk of the scheme, and the parts that matter to a developer are the ones that interact with the build.
A complete methodology section covers:
- Site background, with a summary of the historic environment record entries and previous work.
- Aims and objectives, related to the regional research framework rather than written generically.
- The area to be investigated, shown on a plan, with trench or excavation area locations, dimensions and any exclusion zones for services and trees.
- Machine type and attachment, spoil handling and storage locations, and reinstatement.
- The recording system, survey control and the level of detail for plans and sections.
- Environmental and finds sampling strategies, with sample sizes stated.
- Staffing, with named roles and the supervisor's experience.
- Monitoring arrangements, including how much notice the adviser needs for visits.
- Health and safety, and the interface with the principal contractor's arrangements under the construction regulations.
- A contingency for unexpected discoveries, with a mechanism for agreeing extra time and cost.
Two of those repay attention. Spoil storage is a site logistics question and it has stopped work on constrained sites where nobody allocated space for it, so coordinate it with the Construction Management Plan. And the contingency clause is what prevents a two day stand-off when a wall foundation appears in the corner of a trench.
Where standing buildings are involved, the scheme should cover the recording work as well, at the level agreed, and Historic Building Recording follows a separate set of levels and conventions that the same document can carry.
Post-excavation assessment, analysis and archive
The sequence after fieldwork is fixed and each stage has a deliverable.
Assessment comes first. The contractor quantifies what was recovered, specialists give an initial view on potential, and the report recommends what further work is justified. Then an updated project design sets out the analysis programme, which the adviser approves. Then analysis proper: pottery, animal bone, human remains, environmental samples, metalwork conservation, scientific dating. Then the report, then publication, then deposition of the archive.
Archive deposition is the stage that has become the hardest part, and it is worth saying plainly. Many museums are at or beyond capacity and some have closed to new archaeological archives. Name the intended receiving museum in the scheme, confirm in writing that it will accept the material, obtain an accession number, and understand its charging basis, which is often per box. Where no museum will take the archive, the scheme needs to say what happens instead, and that conversation belongs at the start rather than two years later.
Register the project on the online index for archaeological investigations as the scheme will require, and include the publication route: a local or county journal, a monograph, or a report in a recognised online series depending on the scale of what was found.
Publication and the costs that follow
Budget the tail as a proportion of the whole rather than as an afterthought. A rough planning assumption for a site with real archaeology is that post-excavation, reporting, publication and archive together are at least as large as the fieldwork cost, and on a site with a large finds assemblage or human remains they are larger.
Illustrative example. A 1.5 hectare site where evaluation found Romano-British field boundaries and a small cemetery. Open area excavation of two zones took six weeks. Assessment took three months, including specialist views on the pottery and the human remains. The updated project design proposed osteological analysis, radiocarbon dating of four burials and environmental analysis, which ran for a further five months, with publication in the county journal the following year and the archive deposited with an accession number obtained before fieldwork started. The developer's programme was unaffected after the six weeks on site, because the condition had been drafted in stages. That drafting was worth more than any negotiation on rates.
Timing the work against the construction programme
Sequence the archaeology into the enabling works rather than treating it as a pre-start obstacle. Practical measures:
- Discharge the scheme approval stage as soon as permission is granted, not when the contractor is appointed.
- Carry out fieldwork after site clearance and before any ground remodelling, and give the adviser the notice the scheme requires.
- Avoid programming large open area excavation into midwinter where you can, because short days and wet ground slow recording.
- Coordinate with any unexploded ordnance risk assessment, ground investigation or tree protection, since all four want the same ground at the same time.
- Keep a watching brief provision for the areas outside the excavation zones.
Where an archaeological condition has to be satisfied before work starts, check its exact wording. A condition requiring the scheme to be approved before "development" begins captures demolition and site clearance in many cases, and starting those works first is a breach that is awkward to remedy.
Discharging the condition in stages
Ask for a two or three part condition at the decision stage. Part one, approval of the written scheme and completion of the fieldwork, before development begins. Part two, submission of the post-excavation assessment and updated project design within a stated period after completion of fieldwork. Part three, completion of analysis, publication and archive deposition within a stated period, with the timescale agreed rather than tied to first occupation.
That structure lets the development complete and occupy while the analysis runs, which is the outcome everyone wants, and it gives the authority an enforceable timetable. A single condition tying occupation to publication is the version to argue against, politely, before the decision is issued.
Heritage cases that combine buried archaeology with a standing building need both strands in one document, in the same way that a heritage statement for a listed shopfront has to address fabric and setting together.
PlanScope drafts the archaeological desk-based assessment and heritage narrative that sit in front of a written scheme, and flags where fieldwork results have to be inserted. The written scheme itself is a contractor's document. 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, and archaeological fieldwork must be carried out by a suitably qualified archaeologist.
This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it.
Enter a site postcode on PlanScope to see which heritage and archaeology documents an application is likely to need.
Frequently asked questions
Who writes the written scheme of investigation?
The archaeological contractor appointed by the developer, normally an organisation registered with the Chartered Institute for Archaeologists. The local planning authority approves it, advised by its archaeological adviser. The developer's role is to commission it early, give the contractor the construction information it needs and check that the programme in it matches the build programme.
What is the curator's brief?
A short document issued by the authority's archaeological adviser setting out what the archaeological work must achieve: the area to be covered, the questions to be addressed, the methods expected and the standards to be met. The written scheme is the contractor's response to it. Ask for the brief before quoting, because a scheme written without it usually needs revising.
How long does post-excavation work take?
Months, and on a large site with substantial finds assemblages it can run past a year. Assessment comes first, then an updated project design, then specialist analysis, reporting, publication and archive deposition. Radiocarbon dating and specialist assessment of pottery, environmental samples and human remains all have their own queues.
Can an archaeology condition be discharged in stages?
Usually, and it is worth agreeing the stages up front. A common split is approval of the scheme and completion of fieldwork before development, then post-excavation, reporting, publication and archive as a later stage tied to a timescale rather than to occupation. Get the wording right at the decision stage rather than arguing later.
What happens if something unexpected is found?
The scheme should say. A contingency provision covering an extension of the excavation area, additional recording time and specialist attendance avoids a stand-off on site. For human remains, work stops locally, the coroner is informed and removal needs the appropriate licence. Finds that may be treasure are reported under the Treasure Act 1996.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.