Appeal 6001089

The appeal is dismissed.

Under Article 3(1) and Class A of Part 20, Schedule 2 of the Town and Country Planning (General Permitted Development) (England) Order 2015 as amended (the GPDO), planning permission is granted for the construction of up to two additional storeys of new dwellinghouses immediately above the existing topmost residential storey on a building which is a purpose-built detached block of flats as well as certain associated works. For development to be permitted it must satisfy the limitations set out at paragraph A.1 and the conditions at paragraph A.2 of Class A.

[name] (6) Procedure for applications for prior approval under Part 20 of the GPDO states that where an application relates to prior approval as to the flooding risks on the site, on receipt of the application, the local planning authority must consult the Environment Agency where the development is in an area within [name] 3. The Environment Agency were consulted on the application and did not object to the proposal.

[name] (15) of Part 20, Class A of the GPDO requires the local planning authority to take into account any representations made to them as a result of consultation, and to have regard to the National Planning Policy Framework (the Framework), so far as relevant to the subject matter of the prior approval, as if the application were a planning application. I have considered the appeal on the same basis.

Since the application was determined the Council have adopted the Richmond upon Thames Local Plan (2025) (LP). These policies are relevant insofar as they relate to the matters and only as evidence to support the planning judgement to be made.

There was a previous appeal decision1 (the previous appeal) for the construction of one additional storey to provide 5 additional residential flats, which in accordance with case law is a material consideration as it is necessary to have consistency in decision making. This appeal differs only in that further information has been submitted with regards to flood risk and the flood evacuation plan.

A Flood Risk Appeal Statement prepared by [name], dated October 2025, which includes an updated Flood Evacuation Plan (FEP) has been submitted as part of the appeal. As this document was available to all interested parties and does not materially evolve the scheme, I am therefore content to accept its submission for information purposes and am satisfied that no party with a potential interest in the outcome of this appeal is prejudiced by me doing so.

Before prior approval under Class A can be evaluated, it is necessary to determine whether or not the proposal falls to be considered as ‘permitted development’. The Council accept that the building qualifies as permitted development under this class, and I find nothing that contradicts this conclusion. Of relevance to this appeal, prior approval will be required where, as set out in [name].2 (1) (d) there are flooding risks in relation to the building.

The Council refused prior approval in respect of unacceptable effects on the safety of future occupants in the event of flooding. Accordingly, the main issue is whether prior approval should be granted with regard to flooding risks in relation to the building.

The appeal site is a detached block of flats located at the end of the [name] cul-de-sac. To the front of the site there is car parking and a small, landscaped area and to the rear is a communal garden beyond which is the [name]. The surrounding area is residential, comprising similar style detached blocks of flats. The proposal is for the construction of one additional storey which would provide 5 flats. The appeal site is located approximately 450m upstream of [name], where the tidal section of the channel meets the freshwater river. It is within [name] 3 and is also classified as an area susceptible to ground water flooding.

Paragraph 181 of the Framework states that development should only be allowed in areas at risk of flooding where, any residual risk can be safely managed and safe access and escape routes are included, as part of an agreed emergency plan. The Planning Practice Guidance (PPG) states that to demonstrate to the satisfaction of the local planning authority that the development will be safe for its lifetime taking account of the vulnerability of its users, a site specific flood risk assessment may need to show that appropriate evacuation procedures and flood response infrastructure are in place to manage the residual risk associated with an extreme flood event. It goes onto say that proposals that increase the number of people living in areas of flood risk require particularly careful consideration as they could increase the scale of any evacuation required. 1 APP/L5810/W/24/3343664

A site-specific FRA was undertaken by [name] (July 2021) and an Addendum prepared by [name] (November 2023) which informed the previous appeal. To support the latest application a [name] was prepared by [name] (dated April 2025). As part of the latest planning application a Technical Memorandum2 was submitted on behalf of the [site address] Owners Association, which reviewed these documents and raised concerns with regards to the assumptions on the extent of the flood risk and proposed flood evacuation plan.

A Flood Risk Appeal Statement (FRAS) was prepared by [name] to support the appeal (dated October 2025). This document included the Environment Agency’s Peak Flood Hazard maps dated 2025 and, on this basis, concluded that the site is still located within [name] 3. The Environment Agency confirmed that the FRA has used the most recent model data available.

An updated Flood Evacuation Plan (FEP) has been appended to the FRAS based upon the site’s flood risk of ‘danger for all’. It recommends that residents sign up to the Environment Agency’s Flood Alerts and [name]. Where a flood warning is issued it states that residents should evacuate the site prior to the onset of flooding. The updated FEP includes the same evacuation route to [address] as submitted as part of the previous appeal. During my site visit I observed that the evacuation route along [name] and [address] is approximately a ten-minute walk. In the event of a flooding event, waters could reach depths of up to 2m along this route. Therefore, I conclude that there is a risk that residents, particularly those with reduced mobility, could become stranded by flood waters whilst attempting to evacuate the building and thereby require emergency assistance.

Where it is not possible to evacuate the site without entering flood waters the FEP recommends that residents remain within their properties. The principles of the plan were considered acceptable by the Richmond and Wandsworth Emergency Planning Team in an email dated 19th February 2025, subject to the inclusion of additional recommendations to stock non-perishable food and water for the refuge areas. Whilst the Council’s Planning Report confirms that the Emergency Planning Team recommended minor changes to the FEP, I have not been provided with any evidence to confirm that they find the submitted updated plan acceptable.

As the proposal relates to the sixth floor of the building, I recognise that residents would be safe from flood waters if they remain in their properties. However, they would potentially be cut off for long periods of time until flood waters recede, and it is not clear whether they would still have access to electricity, water and heating and therefore that it would provide safe refuge. Although it is recommended that residents prepare appropriately for this, there are no guarantees that they would sign up to the flood warnings/alerts or prepare for incidents in accordance with the FEP. I also note the concerns of third parties about how these arrangements would be managed in practice, as there is a high degree of turnover of residents within the block, which may also be the case for future occupants of the new dwellings.

Notwithstanding the comments from the Council’s emergency planning team, I have not been provided with details of any discussions which may have taken 2 Prepared by SLR Consulting Limited dated 10 June [address] between the appellant and emergency services nor the likely impacts of flooding on essential services such as electricity, gas, telecommunications, water supply and sewerage. Therefore, based on the available evidence I cannot be certain that the proposal would not place additional, unacceptable burdens on emergency services who would already be under pressure during a flood event. Therefore, based on the submitted evidence and insofar as it is relevant to this case I cannot be satisfied that any residual flood risk can be safely managed for the lifetime of the proposal as required by the Framework.

The Council have put forward a proposed condition in relation to the FEP, however as flooding risks are a condition for prior approval this is not a matter that should be dealt with by way of a condition.

Consequently, I conclude that based on the evidence before me, that the proposal would have an unacceptable effect on flood risk and the safety of future occupants. Therefore, the proposal would not comply with the condition set out at [name].2 (1) (d) of the GPDO and prior approval should not be granted.

I note that concerns have been raised by third parties in relation to the appearance of the proposal, transport and parking, impact on ecology and effects on the living conditions of neighbouring residents and future occupants. I also recognise that the site adjoins the Broom Water Conservation Area and is in proximity to a number of Buildings of [name]. However, as I am dismissing the appeal on different grounds there is no need for me to address these in further detail.

The appellant has raised concerns with regards to the lack of engagement of officers during the determination of the application, however this is not a matter for me in the determination of the appeal.

For the reasons given above the appeal should be dismissed.