Heritage Impact Assessment: what a Heritage Statement should include

 

A Heritage Impact Assessment explains the significance of heritage assets affected by a development proposal and, crucially, what effect the proposal would have on that significance. You may also see the document called a Heritage Statement or a Statement of Heritage Significance. The names overlap in practice, but the assessment has to do more than provide a history of the building or area.

The August 2026 National Planning Policy Framework has made the terminology clearer. Policy HE5 requires proposals affecting heritage assets to be accompanied by a proportionate assessment of significance, including any contribution made by setting, and of the potential effect of the proposal. Annex C now names the national information requirement as a Heritage impact assessment.

This page explains when one is needed, the difference between the common names, what the August 2026 NPPF expects, how much detail is proportionate, and what a useful assessment should actually contain.

 

Heritage Impact Assessment, Heritage Statement or Statement of Heritage Significance?

 

There is no need to get trapped by the title. What matters is whether the submitted information answers the policy questions.

Statement of Heritage Significance is the expression used in Historic England Advice Note 12. It concentrates on understanding what is significant about the affected heritage asset and why.

Heritage Statement has become a widely used planning shorthand for a document dealing with heritage significance and the effect of a proposal.

Heritage Impact Assessment is now the clearest national-policy term. Annex C of the August 2026 NPPF uses that name for the information required by HE5. Historic England also describes a Heritage Impact Assessment as going beyond a statement of significance by setting out the effect of the proposal on that significance.

In practice, a well-prepared document will usually do both jobs: understand significance first, then assess impact. Calling a report a Heritage Statement does not make it deficient, and calling it a Heritage Impact Assessment does not make it adequate. The content is what matters.

 

When is a Heritage Impact Assessment needed?

 

HE5 applies where a development proposal affects a heritage asset. That can include direct works to the asset itself, development within its surroundings, or a proposal elsewhere which changes the way the asset is experienced or understood.

Relevant assets can include:

• listed buildings
• conservation areas
• scheduled monuments
• registered parks and gardens
• registered battlefields
• protected wreck sites
• World Heritage Sites
• non-designated heritage assets, including locally listed buildings where relevant
• ridge and furrow and other historic field systems where the evidence shows heritage significance
• heritage assets with archaeological interest

You do not need to be physically altering a listed building for heritage assessment to be relevant. A new house, extension, renewable-energy scheme or change of use some distance away can affect the setting of a heritage asset. Conversely, proximity alone does not prove an effect: the assessment should identify the actual relationship and whether it matters to significance.

 

The August 2026 NPPF requirement: HE5 and Annex C

 

Policy HE5 – Assessing effects on heritage assets is now the main national decision-making policy for the assessment itself. It requires the application material to cover:

• the significance of the heritage asset or assets affected
• any contribution made by their setting
• the potential effect of the proposal on that significance
• a level of detail proportionate to the importance of the asset and no more than is necessary to understand the potential effect
• reference to the relevant Historic Environment Record
• appropriate expertise where necessary

Annex C then describes the heritage information requirement as a Heritage impact assessment. This is a useful change because it makes clear that the work cannot stop at describing significance.

HE5 also provides a new, explicit framework for the conclusion. The assessment should identify whether the proposal would have:

• a positive effect, where significance is enhanced or better revealed
• no effect on significance
• harm to significance
• substantial harm, where a key element of significance would be seriously affected
• total loss of significance

The policy expressly says that it is the effect on significance rather than the scale of the development which matters. A physically small alteration can therefore matter greatly to a highly sensitive part of a heritage asset, while a larger proposal may have little or no heritage effect in the right circumstances. For the wider decision-making balance, see our guide to heritage significance and harm.

 

Start with significance, not with the proposed works

 

A common weakness in Heritage Statements is to describe the proposal in detail and then add a few paragraphs about the age or listing grade of the building. That reverses the proper sequence.

First establish why the asset is important. Under the current NPPF, heritage significance can arise from archaeological, architectural, artistic or historic interest. Significance may derive from the physical fabric of the asset, its plan form, construction, alterations, associations, group value, landscape relationships and its setting.

The statutory list entry is a starting point for a listed building, not a complete inventory of everything protected or significant. Older list descriptions can be particularly brief. A feature omitted from the description is not therefore automatically unimportant or outside the listing.

A proportionate assessment should distinguish between features which make a strong contribution to significance and those which make little, no or even a negative contribution. That makes the impact assessment much more useful because it shows what change actually matters.

 

Setting must be assessed where it contributes to significance

 

HE5 expressly includes any contribution made by setting. The current NPPF defines setting as the surroundings in which a heritage asset is experienced, and its extent is not fixed.

That means a Heritage Impact Assessment should not simply draw an arbitrary 50 metre, 250 metre or 1 kilometre circle and assume every asset inside it is affected. A search radius may be a useful way of identifying possible assets, but the assessment then has to consider the real relationship between the site and each relevant asset.

Views can be important, but setting is not only visual. Historic relationships, movement, noise, activity, smell, topography, landscape structure and the way an asset is approached or experienced can all be relevant in the right case. Our dedicated guide to the setting of a heritage asset explains the current policy, statutory duties and case law in more detail.

 

Listed buildings: the assessment informs a statutory duty

 

Where the proposal involves listed building consent, section 16(2) of the Planning (Listed Buildings and Conservation Areas) Act 1990 requires the decision-maker to have special regard to the desirability of preserving the building or its setting or any features of special architectural or historic interest which it possesses.

Where planning permission is being considered for development affecting a listed building or its setting, section 66(1) imposes the corresponding special-regard duty.

The Heritage Impact Assessment does not replace those duties. Its job is to provide the evidence which allows the authority to understand the asset, the proposed change and its effect properly. Where both planning permission and listed building consent are required, the same core heritage evidence can usually inform both applications provided it addresses the different proposals and statutory considerations accurately.

 

Conservation areas need more than a generic character paragraph

 

For land or buildings in a conservation area, section 72(1) of the 1990 Act requires special attention to be paid to the desirability of preserving or enhancing the character or appearance of that area.

The starting point should therefore be the special architectural or historic interest of the conservation area and the elements which contribute to it. An adopted conservation area appraisal is often extremely useful, but it should not be copied uncritically. The assessment still needs to relate the appraisal to the particular site and proposal.

Development outside a conservation-area boundary can also affect the significance of the conservation area through its setting under national policy, even though the wording and geographic reach of the section 72 duty itself are different.

 

Archaeology may require its own evidence

 

HE5 is explicit where a proposal involves, or has the potential to involve, a heritage asset with archaeological interest. An appropriate desk-based assessment should be undertaken and, where necessary, a field evaluation.

This is not something to leave until after the design has been fixed. Archaeological evidence can affect the layout, foundation strategy, access, drainage and whether preservation in situ is feasible. See our separate guide to archaeology and planning applications.

 

How much detail is proportionate?

 

The NPPF deliberately does not prescribe a page count. HE5 says the detail should be proportionate to the importance of the asset and no more than is necessary to understand the potential effect.

A modest, reversible alteration to a less sensitive part of a Grade II building may need a short focused assessment. A major development affecting a Grade I building, scheduled monument or World Heritage Site may require extensive archival research, site analysis, verified views, specialist disciplines and assessment of cumulative effects.

Proportionate does not mean superficial. A two-page document can be excessive if there is no heritage effect, and inadequate if it fails to identify an important element of significance. The scope should respond to the asset, the proposal and the likely effect.

 

What should a Heritage Impact Assessment contain?

 

There is no single statutory template, but a useful assessment will normally cover the following.

1. The proposal and scope

Identify the site, the consent sought and the works or development being assessed. Explain which heritage assets could realistically be affected and why others identified in an initial search have been scoped out.

2. Sources and methodology

Record the sources used, including the relevant Historic Environment Record, National Heritage List for England, conservation area appraisal, historic maps, archives, previous investigations and site inspection. Explain any important limitations in the evidence.

3. Historical development

Include enough history to explain the asset, not history for its own sake. The useful question is how the place evolved and which surviving features or relationships carry heritage interest today.

4. Assessment of significance

Identify archaeological, architectural, artistic and historic interest as relevant. Explain the contribution of fabric, spaces, features, associations and setting. Avoid treating every part of an old building as equally significant without analysis.

5. The contribution of setting

Where relevant, explain how the surroundings contribute to significance or to the ability to appreciate it, and how the development site relates to those surroundings.

6. Effect of the proposal

Work through the actual changes. Identify which elements of significance are affected, how they are affected and whether the result is a positive effect, no effect, harm, substantial harm or total loss under HE5.

7. Avoidance, design response and mitigation

Show how understanding significance influenced the proposal. If harm was identified, explain the alternatives considered and how design, materials, siting, scale, detailing, recording or other measures avoid or minimise it.

8. Policy and statutory conclusion

Apply the relevant statutory duties, development plan heritage policies and current national decision-making policies. Where harm remains, identify it clearly so that the correct HE6 or HE7 balance can be applied rather than disguising it with vague wording.

 

The Historic Environment Record is not optional background

 

HE5 specifically says that the relevant Historic Environment Record should be referred to. The HER can contain archaeological events, previous investigations, locally recorded assets and information which is not apparent from a simple search of the National Heritage List for England.

For very small proposals, the extent of investigation should still be proportionate, but a report which claims compliance with HE5 while ignoring an obviously relevant HER is difficult to defend.

 

A site visit can be essential

 

Desk research cannot always show how a building, space or setting is actually experienced. Where physical fabric is being altered, a competent inspection may be necessary to understand construction, phasing and the significance of features. Where setting is in issue, the assessor may need to experience relevant approaches, views and relationships on the ground.

Photographs should assist the analysis rather than act as decoration. Annotated plans, historic maps and clearly located viewpoints can often explain a heritage effect more efficiently than several pages of prose.

 

Can the heritage assessment sit inside another document?

 

Yes, where that is sensible. The NPPF requires the assessment; it does not say that every proposal must have a completely separate PDF with a particular title.

Government Planning Practice Guidance and Historic England advice have long recognised that heritage information can sometimes be incorporated into a Design and Access Statement, avoiding unnecessary duplication. A Planning Statement can also cross-reference the specialist heritage evidence and explain its planning consequence.

The important thing is clarity. If the information is spread across several documents, an officer, consultee or Inspector should still be able to identify the assessment of significance, impact and conclusions without having to reconstruct the case from scattered references.

 

Does a missing Heritage Impact Assessment make an application invalid?

 

This needs a careful answer because policy information requirements and legal validation are related but not identical.

HE5 and Annex C now make the Heritage Impact Assessment a national policy information requirement where heritage assets are affected. DM2 says local validation lists should include information specified by relevant national decision-making policies.

However, the legal machinery for deciding whether an application is valid still sits in legislation, including section 62 of the Town and Country Planning Act 1990 and the Development Management Procedure Order. Local requirements also have to satisfy statutory tests of reasonableness and materiality, and an up-to-date local validation list matters.

So if an authority refuses to validate an application because heritage information is missing, do not rely on labels alone. Check:

• whether HE5 is genuinely engaged by the proposal
• what heritage information has already been supplied
• the council’s current local validation list
• whether the request is proportionate to the asset and likely effect
• the statutory basis for the validation requirement

Our guide to planning application validation requirements explains those rules in more detail.

 

When should you use a heritage specialist?

 

HE5 says appropriate expertise should be employed where necessary. Not every heritage assessment needs an expensive specialist report, but expertise becomes increasingly important where the proposal involves:

• direct alteration or demolition of significant historic fabric
• a Grade I or Grade II* listed building or another asset of the highest significance
• complex building archaeology or uncertain phasing
• archaeological potential requiring desk-based assessment or field evaluation
• significant setting effects, verified views or landscape analysis
• a World Heritage Site or its Outstanding Universal Value
• disagreement with the authority about significance or harm
• a proposal which is likely to proceed to appeal

Getting the heritage analysis early can save money. The best time to discover that a wall, roof structure, view or historic relationship is important is before the design is fixed and an application is submitted.

 

Common Heritage Statement mistakes

 

• Treating the list description as the whole assessment: it is primarily an identification record, not a complete statement of significance
• Writing a history essay: background is useful only where it helps explain present significance
• Describing significance but not impact: HE5 and Annex C now expressly require assessment of the potential effect
• Using an arbitrary radius as the setting assessment: distance can help scope assets but does not define setting
• Assuming no visibility means no effect: setting can involve non-visual and historic relationships
• Calling every change harmful: HE5 expressly recognises positive effects and no effect
• Calling every harm “minor” without explaining significance: the conclusion must follow from the identified heritage interest and the actual change
• Ignoring the Historic Environment Record: HE5 specifically requires it to be referred to
• Using outdated NPPF terminology: the August 2026 Framework now provides the HE5 effect categories and HE6/HE7 decision framework
• Hiding residual harm: if harm remains, identify it clearly so the correct planning balance can be applied

 

Heritage Impact Assessment checklist

 

• Have the relevant heritage assets been identified rather than every asset within an arbitrary radius
• Has the relevant Historic Environment Record been consulted
• Does the assessment explain why each relevant asset is significant
• Has any contribution made by setting been addressed
• Does the proposal description match the submitted drawings and consent sought
• Does the report assess the effect on significance rather than merely describe physical change
• Is the HE5 conclusion clear: positive effect, no effect, harm, substantial harm or total loss
• Have design changes, avoidance and mitigation been explained
• Are the correct statutory duties identified for listed buildings and conservation areas
• Is the level of detail proportionate and supported by appropriate expertise where necessary
• Does the conclusion link to the correct HE6 or HE7 decision-making framework

 

Relevant legislation, policy and guidance

 

• Planning (Listed Buildings and Conservation Areas) Act 1990, section 16(2) – the special-regard duty when determining listed building consent
• Planning (Listed Buildings and Conservation Areas) Act 1990, section 66(1) – planning permission affecting a listed building or its setting
• Planning (Listed Buildings and Conservation Areas) Act 1990, section 72(1) – preserving or enhancing the character or appearance of conservation areas
• Town and Country Planning Act 1990, section 62 – application information and local information requirements
• Town and Country Planning (Development Management Procedure) (England) Order 2015, article 11 – validation and local-list requirements
• National Planning Policy Framework, August 2026 – particularly HE4 to HE7 and Annex C
• Planning Practice Guidance: Historic environment – useful guidance on significance, setting and assessment, but its NPPF paragraph references and older harm terminology have not yet been fully recast for the August 2026 Framework
• Historic England Advice Note 12: Statements of Heritage Significance – useful staged guidance on assessing significance and proportionality, read alongside the current NPPF

 

Where to go next

 

If the difficulty is deciding what matters about the asset, continue to heritage significance and harm. If the proposal is nearby rather than physically altering the asset, see the setting of a heritage asset.

For applications involving a listed building, see listed building consent. Works affecting a scheduled monument may also require Scheduled Monument Consent. For supporting application documents more generally, our guides cover Design and Access Statements, Planning Statements and validation requirements.

Conservation, Heritage & Protected Sites

 

Heritage Impact Assessment Page Updated: 24th August 2026