Historic Environment Records: getting and using the data

A historic environment record search is the first piece of archaeological evidence most self-builders buy, and it is usually the lowest-cost way to find out whether a plot carries a real risk of a trial trenching condition. The record is held by the county archaeological service, a unitary authority or a national park authority, and in Greater London by a single London-wide record. You send a site boundary and a search radius, you get back monument records, event records and copies of previous reports, and that package is the baseline for an archaeological desk-based assessment.

What the record is not is a list of what is buried on your site. It is a list of what somebody has previously recorded.

What a record holds and what it does not

A typical return contains several layers of information. Monument records describe known assets: a cropmark enclosure, a medieval moat, a demolished mill, a findspot where a hoard was ploughed up in 1953. Event records describe previous investigations, including evaluations, watching briefs and excavations, each with a result. Alongside those sit copies of designation data, historic landscape characterisation, transcriptions from aerial photography, and grey literature reports that were never formally published.

The record grows by accretion. Some entries came from an antiquarian note, some from a developer-funded evaluation last year, and the confidence attached to each varies enormously. A monument record is not a statement that something exists, and its mapped position may be a point where a linear feature runs for 400 m.

The Levelling-up and Regeneration Act 2023 placed a duty on local authorities in England to keep and maintain a historic environment record. Commencement and the detailed requirements are worth checking at the time you need them, because the provisions have been brought into force in stages.

What the record cannot do is tell you whether permission will be granted, or whether the county archaeologist will recommend a condition. That judgement comes later, from the assessment built on the data.

Requesting a search and what it costs

The process is the same almost everywhere.

1. Identify the correct record holder for the site, which is the county council in two-tier areas, the unitary or national park authority elsewhere.
2. Send a request with a red line boundary, a national grid reference and a search radius, usually 500 m for a single plot and 1 km for anything larger.
3. State the purpose, because most services charge a commercial rate for planning-related searches and a reduced or nil rate for research and community projects.
4. Ask specifically for event records and grey literature as well as monument records, because some services supply monuments by default.
5. Allow two to three weeks. Some services are faster and a few are much slower.

Ask for the data in a usable form. A spreadsheet of records with grid references and a GIS layer or a plotted figure is worth more than a PDF list, particularly if a consultant will be reading it.

Some of the same information is available through national aggregation services and through the datasets published on the national planning data platform, which is useful for a first look. It is not a substitute for the record itself, because aggregated feeds lag behind the local record and rarely carry event data or grey literature.

Reading monument and event records

Each record carries an identifier, and those identifiers are what you cite later. Learn to read three fields before anything else.

The record type tells you whether the entry is a monument, an event, a find or a building. The source tells you where the information came from, which is the difference between a geophysical survey and a nineteenth century antiquarian report. The spatial accuracy or precision field tells you how much to trust the mapped position, and it is the field most often ignored.

Event records are the ones that change decisions. An evaluation carried out 60 m from your boundary in 2019 that found a Roman ditch system tells you more about your risk than a monument record for a findspot 300 m away. Read the event report if the service will supply it, because the trench plan will show how close the investigation actually came to your plot.

Negative evidence and why it is worth having

An event record showing that somebody dug 12 trial trenches on the adjoining field and found nothing is a positive result for your application. Negative evidence reduces the archaeological potential of the area, and it is the single most useful thing a search can return.

It is also routinely underused. Assessments tend to list the positive records and stay quiet about the investigations that came up empty, which leaves the county archaeologist to reach a cautious conclusion. Set the negative evidence out explicitly, with the trench locations relative to your site, and the case for a lighter condition becomes much easier to make.

Absence of any record is different from negative evidence, and the distinction matters. A blank area on the record may mean nothing has ever happened there, and on a site that has never been developed or surveyed that is a reason for caution rather than comfort.

Using the data in a desk-based assessment

The record is the backbone of an archaeological desk-based assessment, which also draws on historic mapping, geological data, aerial photography and a site walkover. The Chartered Institute for Archaeologists publishes the standard and guidance most assessments follow, and county archaeologists read against it.

The assessment moves through four steps: establish the baseline from the record and other sources, characterise the archaeological potential by period, assess the significance of any assets including the contribution of setting, and set out the likely impact of the proposal with options for mitigation.

Where potential is real and cannot be resolved from desk sources, the usual next step is an archaeological field evaluation, commonly geophysical survey followed by trial trenching. Getting that done before determination rather than by condition gives you certainty on cost, and on a small plot it often costs less than the design changes a late discovery would force.

Where standing buildings are involved, the record also feeds the significance section of a heritage statement. Councils usually expect a suitably qualified author for archaeological work, and professional review is strongly advised.

Where the record disagrees with national datasets

Conflicts are common and each has a right answer.

For designations, the National Heritage List for England is definitive. A scheduled monument, a listed building or a registered park is defined by the list entry and its mapping, and where the local record shows something different, the national list wins. The same applies to the extent of a listing and to curtilage questions, where what the listing captures is decided by the entry and by law rather than by a local record.

For non-designated assets and for the archaeological baseline, the local record is the better source, because it holds material that never reaches a national dataset. For conservation area boundaries and article 4 directions, the local planning authority's own mapping governs, and records of former designations can persist in datasets after the designation itself has gone, which is one of several ways that constraints lapse or are revoked without the maps catching up.

Where two sources disagree, say so in the assessment and explain which you have relied on. A reviewer who spots an unexplained discrepancy will ask about everything else.

Citing the source properly

Record data is licensed, not free to reproduce at will. Cite the record holder by name, the date of the search, the search radius and the individual record identifiers you rely on. Reproduce the copyright and licence statement the service supplies with its data.

Do not paste the full dataset into an appendix unless the licence permits it. A table of the records relied on, with identifiers, is what an assessment needs anyway, and it is far more readable than 40 pages of exported rows.

To see which supporting documents a plot with archaeological potential is likely to need, enter the postcode on PlanScope and work from the list it produces.

PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.