Planning Aspects: The NPPF’s New Heritage Tests Explained

With the new National Planning Policy Framework (NPPF) landing just 10 days ago, one of the more subtle changes that has gone under the radar of most of the industry commentary concerns heritage assets, namely the new test on significance impacts and their involvement and weighting within the planning balance.

Previously the test centred around proving (or indeed disproving) that any impact on the significance of designated heritage assets (such as Listed Buildings of any grade) or its setting would constitute “less than substantial harm”. If a development proposal was found to cause either a “substantial” level of harm or even “total loss” of significance, the scheme would be refused, and that was that. It was previously asserted that only where “less than substantial harm” was demonstrated could the public benefits of a scheme be weighed against this and result in potential approval of the scheme.

The situation now applying across England and it’s designated heritage assets represents a materially different approach in the form of policies HE5 and HE6.

For starters, the familiar “less than substantial harm” threshold test has been replaced by HE5(2)(a-d). Four categories now frame the assessment of impact, starting with a positive effect, which is where the significance of a heritage asset would be enhanced or better revealed (1), no effect on significance (2), harm to significance whether directly or through its setting (the degree of which should be identified)(3), and lastly, the total loss of significance (4). It is a much simpler, more transparent policy architecture that encourages the much-needed clarity for the matter.

New Policy HE6 then sets out how these assessed effects should be weighted within the planning balance. Irrespective of whether the effect on an asset is positive, none, some harm, or total loss, as pre HE6(1), the weight this attracts should be “substantial”. Proposals delivering a positive effect should be supported, and only where substantial harm would be caused to a key element of an asset’s significance, or where total loss would occur, should refusal follow under the revised Framework.

Continuing the new NPPF’s theme of expediency and efficiency, heritage assessments (both of the asset’s significance and the potential effect of a development proposal on that significance) are expected to be concise and proportionate to the asset’s importance. This reinforces the Government’s broader ambition to streamline the planning process while ensuring heritage considerations remain robust and appropriately evidence‑led.

Overall, while the terminology has evolved, the underlying objective remains unchanged. Designated heritage assets continue to enjoy strong protection within the planning system, but the revised Framework arguably provides a clearer and more practical mechanism for assessing and weighing impacts. In particular, the explicit recognition of positive effects represents a welcome shift, acknowledging that development can enhance, reveal and secure the long‑term future of heritage assets rather than merely avoiding harm.

For many planning consultants and developers, heritage issues arise not through direct intervention in Listed Buildings or Scheduled Monuments, but through development in their wider vicinity, where questions of significance and setting still become material. The revised approach should prove more straightforward in these circumstances, directing attention to the actual effect of a proposal on significance rather than protracted debates over terminology and harm thresholds.

Heritage policy has therefore been modernised in a way that maintains its conservationist intent while enabling a more practical and pragmatic approach to be taken where appropriate. On our projects here at Waypoint Planning that interact with or even indirectly affect designated heritage assets, we will continue to commission proportionate heritage assessments to fully understand significance, effect, and potential harm, and using this to inform any mitigation measures as part of a robust and evidence-backed planning case.

For more commentary on the new NPPF and analysis of important changes, as well as what this means for landowners, developers, and council’s decision-making, follow us on social media.

For further information please get in touch with our Planning Consultancy Team to discuss on advice@waypointplanning.co.uk or 01284 700727.