Windsor Trinity Yard appeal fails over overlooking

The Windsor Trinity Yard appeal has been dismissed after a Planning Inspector found unacceptable overlooking of neighbouring homes, even though the heritage harm caused by redevelopment was outweighed by the scheme’s benefits. The decision, issued on 9th October 2026, concerns a proposed mixed-use redevelopment behind St Leonard’s Road in central Windsor.

Inspector H Nicholls considered proposals by Sorbon Estates for a net increase of 15 flats and seven ground-floor Class E commercial units in Trinity Yard, together with changes to adjoining St Leonard’s Road properties. The scheme affected a surviving historic builder’s yard in the Inner Windsor Conservation Area, close to a Grade II listed residential terrace.

The distinction is important for urban regeneration schemes. The Inspector accepted much of the applicant’s case on heritage, townscape, housing delivery and future residents’ amenity, but concluded that fixed windows and upper floors would expose existing neighbours to undue overlooking. A shortage of housing land did not justify that effect.

What the Windsor Trinity Yard appeal proposed

The appeal, reference 6009005, related to 59 to 61 St Leonard’s Road and adjoining land at Trinity Yard, Windsor SL4 3BX. It followed Royal Borough of Windsor and Maidenhead’s refusal of outline application 25/00460/OUT. The proposed redevelopment would retain some older fabric but demolish other buildings and construct a courtyard scheme reaching approximately three storeys.

The application description included work to create or alter five residential units above the St Leonard’s Road commercial frontage, a bridge-like first-floor bedroom extension over the Trinity Yard access, and a new development in the yard with 15 homes on upper floors and seven commercial units below. The Inspector recorded that five flats in the frontage had already been created under separate permissions, apart from the additional flying bedroom extension. The appeal therefore concerned a net gain of 15 homes rather than 20.

Only landscaping was reserved for future approval. The position, height, design and window arrangements were not free to be redesigned later through reserved matters. That point subsequently mattered when the Inspector considered whether a planning condition could remedy the neighbouring-privacy problem.

The proposal also included parking, cycle storage, refuse arrangements and new landscaping. A unilateral planning obligation dated 10th July 2026 offered carbon-offsetting provision, a review mechanism for potential off-site affordable housing and refuse-management arrangements. The Council accepted that these measures overcame its fifth refusal reason, but they could not address the remaining design concerns.

Why heritage objections were not decisive

Trinity Yard contains surviving buildings associated with a nineteenth-century builder’s yard, subsequently altered but still recognisable as a rare industrial courtyard in Windsor. The Inspector identified it as a non-designated heritage asset contributing positively to the character and significance of the Inner Windsor Conservation Area.

The development would remove most of those older buildings while retaining part of the main central block. A condition survey indicated that repair and reuse would be prohibitively expensive in substantial areas. The Inspector accepted that this would cause harm through the loss of historic fabric and a modest erosive effect on the conservation area.

That was not the same as finding unacceptable harm to every heritage asset nearby. The Grade II listed terrace at 62 to 96 Grove Road would experience a changed rear outlook, but its architectural and historic significance would not be harmed by the proposed buildings in its setting. The Inspector also regarded the massing, brick detailing, roofs and courtyard layout as broadly responsive to the local character.

Under local heritage policy and the revised national planning framework, the heritage losses still required serious consideration. However, the accepted evidence about the condition of the yard and the benefits of new town-centre housing, continued employment space and improved buildings provided a sufficient justification. The Inspector expressly concluded that the heritage harms were outweighed by those benefits.

For a practical explanation of different protection regimes, see Planning Geek’s conservation areas guide. This decision does not establish that demolishing non-designated heritage buildings is usually acceptable: the condition, significance and benefits of this specific proposal were central.

Overlooking of Grove Road and Temple Road proved fatal

In the Windsor Trinity Yard appeal, the Council’s Borough Wide Design Guide SPD 2020 was particularly relevant. It recommends a 20-metre rear-to-rear distance for directly facing two-storey houses, with greater distances for taller development. Its table indicates 26 metres for buildings above two storeys, or 30 metres where the relationship is between a two-storey house and a taller block of flats.

Rear windows of properties at 80 to 88 Grove Road would sit around 23 to 24 metres from the proposed southern elevation. That distance was not treated as a rigid statutory exclusion zone. The Inspector accepted that the new building would not be oppressive or cause an unacceptable loss of outlook. The problem was elevated second-floor windows directly overlooking rear rooms and the most sensitive first three metres of residents’ gardens.

The Inspector found no creative arrangement, such as a materially revised window orientation, capable of protecting existing occupants. Although development in compact town centres may sometimes justify less conventional separation, its density does not remove the requirement to demonstrate acceptable privacy.

A separate issue arose at 15 to 21 Temple Road. New upper-level windows and dormers at the northern end of the eastern elevation would give close-range views over modest rear gardens and towards neighbouring rear windows. These were not all direct window-to-window relationships, but the angles were insufficiently oblique to prevent a harmful sense of overlooking.

The assessment was carefully differentiated. Other Temple Road houses, including 23 to 35, would not suffer the same effects because the retained boundary wall, absence of directly facing windows and separation distances limited the impact. The Inspector also accepted that the daylight and sunlight assessment did not show material harm. Privacy, rather than general bulk or overshadowing, was the decisive harm.

Crucially, the detailed layout was part of the outline application. The Inspector considered that an approval condition could not sufficiently alter the identified windows to make the development acceptable. Practitioners should resolve these relationships at design stage rather than assuming privacy screens or future conditions can rescue a submitted scheme.

Why future residents’ conditions were treated differently

The proposed courtyard created unusually close relationships among some new flats. The decision identified instances of approximately eight metres between the bedroom of one flat and the living room of another, with other facing habitable-room windows around 11.5 metres apart. Some distances fell materially below the 15-metre guidance applicable to taller courtyard blocks.

However, the Inspector accepted those relationships in their setting. There was a realistic fallback involving conversion of existing buildings to residential use, which would create similarly close relationships. Prospective occupiers could make an informed choice about a compact central location, unlike established neighbours whose privacy would be worsened by the development.

Some flats would have small balconies and others no dedicated external amenity space. The courtyard might feel more like a shared spillover space serving ground-floor shops than a private residential garden. Nevertheless, accessible open spaces including Alexandra Gardens, Bachelors Acre and Windsor Great Park supported an acceptable outcome in this particular town-centre context.

This is not a rule that future residents deserve less protection. It demonstrates that an Inspector can evaluate the quality of a proposed living environment differently from the imposition of new overlooking on existing homes. An applicant relying on an existing lawful conversion fallback should identify its precise planning status and show why it is genuinely realistic.

The 2026 NPPF and housing shortfall did not save the scheme

In the Windsor Trinity Yard appeal, the Inspector applied the revised National Planning Policy Framework published on 17th August 2026, after inviting both appeal parties to comment on the new policy. Windsor and Maidenhead could demonstrate only a 4.04-year housing land supply. The shortfall carried significant weight in favour of additional homes.

The new Framework’s Policy S4 provides a presumption towards approving development within settlements unless benefits are substantially outweighed by adverse effects, including where national decision-making policies indicate refusal. In this case the Inspector identified conflict with Policies DP3(3), relating to local design standards, and LP2(1)(d)(ii), concerning the protection of neighbours’ privacy and living standards.

The benefits of 15 sustainably located homes, commercial premises, improved energy efficiency and construction employment were real. Nonetheless, the failure to protect existing neighbours meant that national policy did not outweigh the conflict with the development plan taken as a whole. The planning appeal was dismissed.

The outcome illustrates why NPPF policy needs to be applied provision by provision, not as a general housing-shortfall trump card. An Inspector can find that heritage harm is justified and still refuse the same scheme for a distinct and unresolved residential amenity impact.

Practical lessons for mixed-use and backland schemes

The Windsor Trinity Yard appeal reinforces why applicants should plot every facing habitable-room window, garden and elevated viewpoint before settling the envelope of a backland scheme. Separation standards are guidance rather than universal legal minimums, but where the proposal departs from them the submitted design must explain what alternative protects privacy.

An outline application must reserve the matters on which real flexibility will be needed. Reserving landscaping alone will not allow a fundamental reshaping of windows, floors or building elevations later. In a fixed-layout scheme, a condition should not be used as a substitute for a redesigned and properly consulted-upon proposal.

Heritage balance and neighbouring amenity need separate analysis. A persuasive viability and heritage justification may establish the case for replacing deteriorating buildings without proving that the replacement massing and openings protect established homes. Equally, a Section 106 undertaking can overcome a contributions objection without repairing a substantive design defect.

The decision also shows why an officer recommendation of approval is not a guarantee of success on appeal. The Inspector noted that councillors had refused the application against officers’ advice, but assessed the planning merits independently. For applicants reviewing a refusal, Planning Geek’s planning appeals guidance explains the need to identify issues that can actually be won or redesigned.

Source and status: Inspector H Nicholls, appeal decision 6009005, dated 9th October 2026; Planning Inspectorate case record. This is a section 78 Inspector’s determination, not a court judgment. Its findings depend on the submitted scheme and local evidence and do not amend the law.