Heritage Statement or Archaeological Desk-Based Assessment

A heritage statement assesses the significance of heritage assets and the effect of a proposal on them, which in practice means listed buildings, conservation areas, registered parks and the settings of all three. An archaeological desk-based assessment assesses the potential for buried remains on a site and the likely effect of ground disturbance on them. The two documents are often confused because both are labelled heritage, both cite national heritage policy, and both are commonly asked for by the same validation list.

They are written by different professionals, to different standards, and they answer questions that do not overlap. The heritage statement versus archaeological assessment question is usually resolved the same way: if the site has standing heritage interest and ground disturbance, you need both.

Standing heritage against buried heritage

National policy requires an applicant to describe the significance of any heritage assets affected by a proposal, including any contribution made by their setting, in a level of detail proportionate to the asset's importance and sufficient to understand the potential impact. That duty covers designated and non-designated assets, above and below ground.

Where it splits is in method. Standing heritage is assessed by looking at the building or area, reading its history and fabric, and judging the effect of the proposal on what makes it significant. Buried heritage cannot be looked at. It is assessed by establishing what is likely to be there from records and comparable sites, then deciding whether intrusive investigation is needed.

Who prepares each and to what standard

A heritage statement has no single mandatory standard, but Historic England's advice on statements of heritage significance, on managing significance in decision-taking and on the setting of heritage assets sets the expected method. Experienced conservation officers read for that method: a description of the asset, an assessment of what contributes to its significance, an assessment of the proposal's effect on those contributing elements, and a conclusion on harm expressed in the language of national policy.

A desk-based assessment is written to the Chartered Institute for Archaeologists standard and guidance, which prescribes the sources to consult, the study area, the reporting structure and the archiving of the report. County archaeologists check against that standard, and an assessment that has not consulted the Historic Environment Record properly will be sent back.

Councils usually expect a suitably qualified author for both documents, and professional review is strongly advised. A Heritage Statement and an Archaeological Desk-Based Assessment can both be drafted to the right structure with the policy framework in place, and the professional judgement, the site inspection and the record search remain theirs.

The Historic Environment Record and what it holds

Every county or unitary authority maintains a Historic Environment Record, and it is the primary source for a desk-based assessment. It holds recorded monuments and find spots, previous archaeological interventions and their results, historic landscape characterisation, aerial photograph interpretation, and reports from developer-funded work that never reached publication.

Access is usually by a search request, sometimes for a fee, covering a defined study area around the site. That last point matters: a search radius of 250 metres on an urban site and one or two kilometres on a rural one are both defensible, and the assessment should say which was used and why.

An HER search is not the whole evidence base. A competent assessment also uses historic Ordnance Survey editions, tithe and enclosure maps, geological mapping to establish whether deposits are likely to survive, aerial and LiDAR imagery, and any site investigation logs from a geotechnical report. Borehole logs from a ground investigation frequently reveal made ground depths that tell you more about survival than any map.

How significance is described in each

In a heritage statement, significance is described by heritage interest: architectural and artistic, historic, and archaeological interest, with a judgement on the relative contribution of each and of the setting. The effect is then expressed as substantial harm, less than substantial harm, or no harm, because that is the language in which national policy frames the tests.

In a desk-based assessment, the language is potential and importance. The report concludes on the likelihood of remains of a given period surviving on the site, how important they would be, and the likely effect of the proposed groundworks. The conclusion is rarely definitive, which is the nature of the exercise, and a good assessment says what it does not know.

Those different vocabularies are why the documents should not be merged. A single combined heritage chapter asserting less than substantial harm to buried remains of uncertain existence answers neither question properly.

Trial trenching and field evaluation triggers

The desk-based assessment recommends what happens next, and the county archaeologist advises the authority on whether to accept it. Typical outcomes, in ascending order of cost: no further work, geophysical survey, trial trenching as a field evaluation, a watching brief secured by condition, or full excavation in advance of development.

Where evaluation is recommended, there is a choice of timing. Doing it before determination gives certainty and strengthens the application, at the cost of money spent before permission. Securing it by condition defers the cost and the risk, and where remains of real importance are then found the scheme may need redesigning after permission. For a site with high potential and a tight layout, pre-determination evaluation is usually the better commercial decision.

In London, Archaeological Priority Areas identified by the Greater London Archaeological Advisory Service drive much of this, and the relationship with the adviser works much as it does with a county archaeologist elsewhere.

When one application needs both, and how to sequence them

An application needs both where the site contains or adjoins a designated standing asset and involves ground disturbance. A barn conversion within the curtilage of a listed farmhouse, a development in the garden of a listed building, a new building in a conservation area with medieval origins, and works to a church or churchyard all fall into that category.

Sequence the heritage statement first. It establishes the historic development of the site, which is exactly the documentary groundwork the archaeologist needs, and it often identifies the below-ground features worth investigating. Then commission the desk-based assessment, giving the archaeologist the heritage statement and any ground investigation data.

Where fabric will be lost or substantially altered, Historic Building Recording to the appropriate Historic England level is frequently required by condition, and the level needed should be discussed with the conservation officer before the condition is drafted rather than after.

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. This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it.