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What is 'Substantial Harm' to a designated heritage asset?
The level of harm to designated heritage assets (or their setting) frequently forms a point of disagreement between applicants and decision-makers, leading to the refusal of many planning applications. 'Substantial harm' is a key policy threshold in England which is often central to the debate. But what is substantial harm and how do we measure it? This long-contested issue was tested very recently at a public enquiry, in a case involving the proposed installation of a UK Holocaust memorial at Victoria Tower Gardens in Westminster, London. This blog examines how the meaning of substantial harm can be seen to have evolved over time, and what the Victoria Tower Gardens decision could mean for how substantial harm is measured in the future. The concept of substantial harm to a designated heritage asset was introduced in 2012, with the publication of the National Planning Policy Framework [NPPF]. Paragraph 199 of the NPPF (as amended) identifies three levels of harm to the significance of designated heritage assets, substantial harm, total loss, or less than substantial harm. Paragraph 201 goes on to state that, where proposed development will lead to substantial harm to (or total loss of) the significance of a heritage asset, local authorities should refuse consent, unless it can be demonstrated that substantial harm or total loss is necessary to achieve substantial public benefits that outweigh that harm. The NPPF makes clear that instances where public benefits outweigh substantial harm should be "exceptional" in most cases, or "wholly exceptional" in respect of assets of the highest significance [§200]. The NPPF (and its subsequent revisions) do not seek to define substantial harm, instead advocating a balanced judgement, having regard to "the scale of any harm or loss and the significance of the heritage asset" [§203]. As is often the case with national planning policy, the interpretation of substantial harm is a debate that has been contested in the courts. For a number of years, one particular case has been seen to offer some clarity on how to measure this important policy threshold, in the absence of detailed policy or guidance. In the 2013 case of Bedford BC v SSCLG38, the High Court held that in order for harm to designated assets to be considered substantial, "the impact on significance was required to be serious such that very much, if not all, of the significance was drained away… One was looking for impact which would have such a serious impact on the significance of the asset that its significance was either vitiated altogether or very much reduced.". This case sets a particularly high threshold for substantial harm, suggesting that there is very little difference between the substantial harm to, and the total loss of, an asset's significance. The Bedford case was seen by many as providing much-needed clarity on the meaning of substantial harm and the application of the heritage policies within the NPPF. On the 23rd of July 2019, the National Planning Practice Guidance [NPPG] was updated to provide additional clarity on assessing substantial harm. The NPPG at Paragraph 18a-018 states that:   “Whether a proposal causes substantial harm will be a judgment for the decision-maker, having regard to the circumstances of the case and the policy in the National Planning Policy Framework. In general terms, substantial harm is a high test, so it may not arise in many cases. For example, in determining whether works to a listed building constitute substantial harm, an important consideration would be whether the adverse impact seriously affects a key element of its special architectural or historic interest. It is the degree of harm to the asset’s significance rather than the scale of the development that is to be assessed. The harm may arise from works to the asset or from development within its setting.”   The NPPG, like the NPPF, advocates professional judgement. Whilst the NPPG guidance is open to interpretation, it does not appear to explicitly set the bar for substantial harm as high as the Bedford judgement. In this context, it could be perceived that there is some tension between the NPPG's definition of substantial harm and the established Bedford case law. This begs the question – would the Bedford case have been decided differently if the NPPG guidance have been in place at that point in time? Perhaps. Was the NPPG intended as a corrective, following the Bedford judgement? It is possible. As mentioned above, this matter was examined very recently, in respect of a proposed UK Holocaust memorial at Victoria Tower Gardens in Westminster. The case (reference APP/XF990/V/19/3240661) had been called in for determination by the Secretary of State. Planning permission was granted for the memorial on 29th July 2021. In considering how substantial harm should be measured, the inspector stated that: "The applicant relies on the definition of substantial harm (and the calibration of lesser harms that flow from it) set out in the Bedford case, broadly defined as a high test. Westminster City Council on the other hand prefer to rely on the example of substantial harm set out in paragraph 018 of the PPG, a definition, as I understand it from their oral evidence, which sets the test at a lesser height…   …My interpretation of this point, also bearing in mind paragraph 018 of the PPG has been formulated in light of the Bedford judgement, is that there is in fact little to call between both interpretations. Bedford turns on the requirement for the harm to be assessed as ‘serious’ (with significance needing to be very much, if not all, ‘drained away’) in order that it be deemed substantial. Alternatively, paragraph 018 indicates that an important consideration would be whether the adverse impact ‘seriously’ affects a key element of special interest. In both interpretations, it is the serious degree of harm to the asset significance which is the key test. Moreover, in accordance with the logic of the Bedford argument, 018 explicitly acknowledges that substantial harm is a ‘high test’.” I would personally question the view that an asset’s significance being ‘seriously affected’ and ‘very much, if not all, drained away’ can be considered to be one and the same. However, it is perhaps not surprising that the Inspector has tried to regularise what has long been perceived as a conflict between case law and guidance; one that has caused endless debate between practitioners. This decision may provide some clues as to the direction of travel in the interpretation of what constitutes substantial harm, and it will be interesting to see how relevant the Bedford case continues to be in the future. Perhaps the focus will move away from perceived inconsistencies in how substantial harm is measured, and towards the proposals and the associated impacts. The door also appears to be left open as to whether or not it is appropriate to sub-categorise different types of ‘less than substantial’ harm. Ultimately however, assessing whether a proposal causes substantial harm remains a subjective judgement, dependent on the evidence and the specifics of the case. That said, it is important that such a judgement is based on a robust assessment. Various recent cases have illustrated how vulnerable planning permissions can be to judicial review when the evidence presented is found to be flawed or misleading (including both the Heritage Impact Assessment submitted by the applicant, as well as the heritage judgement set out in an LPA's Committee Report). In most cases, we would recommend undertaking an early assessment to understand the significance and sensitivity of the heritage assets which could be affected by a development, in order to understand any potential issues and constraints as soon as possible, and to give an understanding of the site's development potential. If you are seeking advice in respect of development proposals affecting heritage assets and would like to discuss these matters in more detail, please do get in touch.