Appeal 3361565

The appeal is dismissed.

For clarity, I have taken the description of development from the Council’s decision notice and other appeal documents submitted by the appellant, as it is more precise than that given on the application form.

At the time of my site visit, the replacement windows had been installed, the hardstanding laid, and the meter box enclosure constructed. I have therefore determined this appeal on the basis that it is a retrospective proposal.

The appeal concerns the retention of development that is currently subject to an enforcement notice. While the appellant has lodged an appeal against that notice 1, it remains undetermined at the time of my decision. Accordingly, the enforcement notice is treated as a separate matter and has not influenced the outcome of this appeal.

As the appeal site is in a conservation area, I have paid special attention to the desirability of preserving or enhancing the character or appearance of that area, as set out in Section 72(1) of the Planning (Listed Buildings and Conservation Areas) Act 1990.

The main issues are: • the effect of the development on the character and appearance of the appeal building and the area, having particular regard to the John Innes Merton Park Conservation Area; and 1 Appeal reference APP/T5720/C/25/3362172 • whether the development includes effective provision for drainage of surface water run-off and whether it would exacerbate flood risk off-site.

The appeal site comprises a detached dwelling located on a residential street made up of detached and semi-detached dwellings of varying forms and styles. The site lies within the John Innes Merton Park Conservation Area (CA), which principally derives its significance from the informal and irregular street layout associated with the old village of Merton, the mix of suburban houses and their architectural quality, and the generous planting in gardens.

The appeal building forms one half of a pair of detached dwellings, constructed in tandem with [address] (No. 5). Together, these two properties exhibit a consistent architectural language, with matching form, materials, and detailing that contribute positively to the character and appearance of the CA. Their visual symmetry and shared design features provide a coherent streetscape presence, reinforcing the historic and aesthetic value of the CA.

No. 5 continues to retain its original aluminium-framed windows, which remain integral to its architectural character. Prior to the appeal development, the individual pane layout of the appeal building’s fenestration closely mirrored that of its neighbour, establishing a balanced and visually coherent relationship between the two dwellings. This symmetry reinforced their identity as a designed pair and contributed positively to the character and appearance of the CA. The replacement windows, which incorporate applied glazing bars across the full extent of each pane, have disrupted this visual continuity, resulting in the loss of a defining architectural feature that previously allowed the buildings to be read as a unified composition. This alteration has not only diminished their collective contribution to the significance of the CA but has also undermined the original design intent of the development.

I acknowledge that the appellant sought to replicate the fenestration of [address] (No. 9). However, this approach is inappropriate in conservation terms. No. 9 is a distinct historic property with its own architectural identity, unrelated to the paired composition of No. 5 and the appeal property. Mimicking its features introduces a pastiche that undermines the integrity of both buildings, diluting the authenticity of No. 9 and disrupting the visual coherence of the original pair. The transplantation of stylistic elements across unrelated contexts compromises the legibility and significance of established architectural groupings.

The previous hardstanding at the front of the property has been replaced, although its overall extent has not increased, with a flower bed retained behind the front boundary wall. Previously, the visual impact of the hardstanding was softened by the screening effect of the boundary wall, which helped maintain a degree of enclosure and visual containment within the streetscape. The appellant’s evidence indicates that parts of the previous boundary wall were in a state of disrepair when the appellant purchased the property and subsequently collapsed. However, the reduction in the wall’s length has exposed the frontage to public views, increasing the visual prominence and dominance of the hard surfacing. This observation aligns with the findings of the Inspector in a previous appeal at the site 2, where harm to the visual amenity of the area was identified due to the scale of the entrance and the open, hard-surfaced frontage.

The submitted plans indicate that the front boundary wall will be reinstated to its original length, which would help to reintroduce the important screening effect it previously provided in relation to the hardstanding. However, the drawings on which the Council based its decision do not specify the height or finish of the reinstated section. In the absence of this detail, I cannot be confident about the extent of screening the rebuilt wall would offer, nor its effectiveness in mitigating the identified harm. Furthermore, without clarity on its material treatment and proportions, I am unable to assess whether the reinstatement would meaningfully restore lost fabric in a manner that preserves the CA’s integrity.

A meter box has been installed at the front of the property, enclosed within a purpose-built structure positioned on a concrete plinth adjacent to the boundary with No. 9. The enclosure is finished in brick with a shallow sloping roof. However, the brickwork does not appear to match the adjacent boundary wall, making the structure more visually prominent from the street. Whilst it is possible that the bricks may weather to a more sympathetic tone over time, no assurance has been provided to confirm this. Moreover, the enclosure is relatively bulky for housing a meter box, and such structures are not commonly found in the immediate context of [address], further contributing to its incongruous appearance.

As with the hardstanding, reinstating the front boundary wall as indicated on the drawings would help to screen the meter box structure and reduce its visual impact on the CA. However, as previously noted, the drawings on which the Council based its decision do not specify the height of the reinstated section. In the absence of this detail, I cannot be confident about the extent of screening the rebuilt wall would provide, nor its effectiveness in mitigating the harm identified.

The appellant asserts that the location of the enclosure was directed by [name] (UKPN), who appear to have installed the meter box. I note that UKPN’s guidance includes a similar brick-walled structure as an example of an enclosure, and the appellant has provided correspondence with UKPN regarding the installation. However, the evidence before me does not sufficiently demonstrate that the chosen location was the only viable option for siting the meter box, nor has it been shown that a less visually intrusive form of enclosure could not have been achieved. In the absence of such justification, I am not persuaded that the harm resulting from the enclosure was unavoidable.

The replacement windows, hardstanding, and meter box enclosure have caused harm to the historic interest and significance of the CA, and the development therefore fails to preserve or enhance its character or appearance. The Framework advises that great weight should be given to the conservation of designated heritage assets when assessing the impact of development. Whilst the scale and 2 Appeal reference APP/T5720/D/23/3329911 nature of the development result in harm that is less than substantial, it remains of considerable importance and weight. In such circumstances, the Framework requires that this harm be weighed against the public benefits of the development.

The appellant contends that the installation of the windows has delivered environmental and economic benefits. However, no substantive evidence has been provided to demonstrate that these windows offer any clear advantage over the original units. There is insufficient information to confirm that the replacements are more energy efficient, more durable, or more cost-effective in practice. Moreover, no tangible evidence has been submitted to show that any perceived benefits could not have been achieved through a less harmful form of development. Whilst the Framework supports environmental and economic improvements, the small scale of the development and the absence of robust justification mean that the asserted benefits carry limited weight.

Even when taken together, the above stated benefits are insufficient to outweigh the less than substantial harm to the CA and the considerable and important weight it carries.

For these reasons, the development causes unacceptable harm to the character and appearance of the area and fails to conserve or enhance the character or appearance of the CA. Consequently, it conflicts with Policies DMD2, DMD3 and DMD4 of the [name] and Policies Plan 2014 (SPP), Policy CS14 of the Merton Core Planning Strategy 2011 (CS), and Policies D1 and D4 of the London Plan 2021 (LP), which collectively require, in part, that development, particularly in sensitive heritage contexts, respects local character, preserves historic significance, and delivers high-quality, contextually appropriate design. Furthermore, they require that harm to heritage assets should be clearly justified and demonstrably outweighed by public benefits.

The Environment Agency’s flood mapping confirms that the appeal site lies within [name] 1, indicating a low probability of fluvial or tidal flooding. Additionally, the site is identified as being at low risk of surface water flooding. However, the Council has advised that Merton’s Strategic Flood Risk Assessment has recorded two flood incidents within the wider locality. Their occurrence highlights the importance of ensuring that any new development incorporates appropriate drainage measures and does not exacerbate local flood risk. The site's designation within [name] 1 and its low surface water flood risk do not remove the need to consider cumulative flooding impacts.

I note that a formal flood risk assessment has not been submitted. The appellant has confirmed that the development has not increased the area of hardstanding, that the installed surface is permeable, and that the front planting bed has been retained. It has also been confirmed that a soakaway has been installed within the planting bed. These measures are intended to manage surface water run-off and reduce the risk of localised flooding, although in the absence of technical evidence, their effectiveness cannot be fully verified.

The Inspector in the previously referenced appeal concluded that, as the plans indicated no increase in the total area of hardstanding to the frontage, flood risk concerns could be addressed through the submission of additional details. In the present case, the extent of hardstanding remains unchanged, and the site is identified as being at low risk of surface water flooding. Taking a pragmatic approach, I am satisfied that matters relating to surface permeability and the installed drainage system can be clarified through further details, consistent with the mechanism envisaged by the previous Inspector. The submission and approval of these details can be secured by a suitably worded planning condition. Should the information reveal an inadequate approach to flood risk management, the condition would enable the implementation of appropriate mitigation measures.

For these reasons, with the attachment of a planning condition, the development would include effective provision for drainage of surface water run-off and would not exacerbate flood risk off-site. Consequently, it complies with Policies DMF1 and DMF2 of the SPP, Policy CS16 of the CS, and Policy SI13 of the LP, insofar as they require that development manages flood risk proactively through sustainable drainage, permeable surfaces, and site-specific assessments, especially in areas with known flood incidents.

For the reasons given above, the development conflicts with the development plan and the material considerations do not indicate that the appeal should be decided other than in accordance with it. Accordingly, the appeal should be dismissed.