Written schemes of investigation: what gets approved

A written scheme of investigation is the document that unlocks an archaeological condition, and it is approved by someone who is not the case officer. That single fact explains most of the delay developers experience. The scheme goes to the council, the council forwards it to its archaeological advisor, and the advisor reads it against professional standards and against what they know about the ground under your site.

Schemes are rarely rejected outright. They are returned with comments, then returned again, and each round costs two to four weeks on a programme where the groundworkers are already booked. Getting the first version right is worth more than any negotiation afterwards.

Where the requirement comes from

Most archaeological conditions are drafted in three parts. No development until a written scheme of investigation has been submitted to and approved in writing by the local planning authority. The fieldwork to be carried out in accordance with the approved scheme. And the post-excavation assessment, analysis, publication and archive deposition to be completed within a stated period.

The third limb is the one that surprises people, because it extends the obligation years past practical completion. Read the condition carefully before assuming the archaeology ends when the machines leave.

Where a pre-determination Archaeological Field Evaluation was carried out, the scheme can be written against known results and scoped tightly. Where it was not, the scheme has to cover a range of possibilities, which makes it longer, vaguer and more expensive to price.

Who approves it, and on what basis

The approval is the local planning authority's, but the assessment is done by its archaeological advisor. Outside London that is usually a county archaeologist or a shared historic environment service. In London the Greater London Archaeological Advisory Service performs the role.

Advisors assess against professional standards, against the relevant regional research framework, and against their own knowledge of the archaeology in the area. That local knowledge is the part you cannot get from a template, which is why speaking to the advisor before the scheme is drafted saves a round of comments.

They are also assessing whether the contractor can deliver it. Named staff with relevant experience, a realistic programme and a clear management structure carry weight. A scheme that names no one does not.

What the document has to contain

A scheme that gets approved first time has these elements, in this order.

1. Site description, boundaries, existing conditions and the development proposals, with a plan showing the areas affected and the depth of impact.
2. Archaeological and historical background drawn from the Historic Environment Record and from any previous investigation on or near the site, including the results of any evaluation.
3. Aims and objectives, tied to the questions the regional research framework identifies rather than expressed as a general intention to record what is present.
4. Methodology, covering stripping, hand excavation, recording, survey control, finds and environmental sampling.
5. Staffing, with names, roles and relevant experience, and the management and monitoring arrangements.
6. Contingency for unexpected discoveries, including human remains and treasure.
7. Post-excavation programme, archive arrangements and publication proposals.
8. Timetable, with the monitoring points at which the advisor will be invited to visit.

Each of those should be specific to the site. An advisor who reads the same three paragraphs they read last month on a different scheme will treat the rest of the document with suspicion.

Sampling, recording and the environmental strategy

Methodology is where schemes are weakest. Three things need stating in numbers rather than in principle.

The excavation sampling strategy: what proportion of linear features is excavated, how many sections per feature, how discrete features such as pits and postholes are treated, and what happens to structural remains. Stating that features will be "sampled appropriately" tells the advisor nothing.

The environmental sampling strategy: the sample size for bulk samples, which contexts are sampled, who processes them, and which specialists are retained. Environmental evidence is where the research value often sits, and a scheme without a strategy for it reads as one written to a budget.

The recording system: context recording, digital survey, photographic record, and how the site grid is tied to the national grid. Say what software and what standards.

Contingency matters too. Human remains require a licence from the Ministry of Justice before exhumation, and finds that may be treasure must be reported under the Treasure Act 1996. Both need to appear in the scheme with a named responsible person, because discovering them mid-excavation on a Friday is a bad time to look up the procedure.

Post-excavation assessment and publication

Fieldwork is the visible part and often the smaller part of the cost. What follows is assessment of the site records and finds, a decision on what merits full analysis, the analysis itself, and publication.

The scheme should set out the staged approach, with an assessment report produced within a stated period after fieldwork, and a decision point at which the level of analysis and the publication route are agreed with the advisor. Publication can range from a note in a county journal to a monograph, and tying yourself to the top of that range before you know what was found is unnecessary.

Include the timetable. An open-ended commitment to publish "in due course" is the single most common reason a condition sits undischarged five years after the houses were sold.

Archive deposition and the museum problem

Every investigation generates an archive of records and finds, and that archive has to go somewhere. Museums in several parts of England have limited or closed their collecting, and most that still accept material charge a deposition fee calculated by box.

Identify the receiving museum before fieldwork starts and get its agreement in writing, including its requirements for packaging, documentation and fees. Where no museum will accept the material, say so in the scheme and set out what is proposed instead, because the advisor will ask.

Registering the investigation on the national online index of archaeological investigations is standard practice and is usually a requirement of the scheme. It costs nothing and it is often forgotten.

Timescales and discharging the condition

Budget four to eight weeks for approval of the scheme, longer where the advisor is part-time or covering several authorities. The formal discharge of the condition is a separate application to the council, determined in up to eight weeks, with a fee per request set by the national fee regulations.

Where the condition has three limbs, each is discharged at a different time, and the last one may fall due long after the site is occupied. Keep the condition on a tracker and keep the correspondence, because a buyer's solicitor will ask for the discharge evidence. The overlap with other consented obligations, such as habitat delivery, is worth mapping too, as archaeology and biodiversity net gain on the same site sets out.

Why schemes get sent back

The recurring reasons are short and fixable.

Aims not tied to a research framework. Sampling expressed in adjectives. No environmental strategy. No named staff. No contingency for human remains or treasure. No receiving museum identified. An open-ended post-excavation timetable. And the most common of all: a generic template with the site name changed, submitted in the hope that nobody reads it closely.

They do read it closely. Give the advisor a document that shows you understand what is under the site, and the approval usually comes back with minor comments rather than a request to start again. The background for that understanding comes from the Archaeological Desk-Based Assessment, and where standing buildings are affected as well, from the Historic Building Recording brief agreed alongside it.

This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it. Councils usually expect a suitably qualified author for archaeological work, and professional review is strongly advised. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.