Westminster roof terrace appeal doubles capacity to 120

The Westminster roof terrace appeal has succeeded after an Inspector allowed an office building near Victoria Station to double its permitted terrace capacity from 60 to 120 people and extend weekday use until 10.30pm. The decision was issued on 9th October 2026.

At Belgrave House, 76 Buckingham Palace Road, the rear fifth-floor terrace sits only around 15 metres from the nearest residential windows. Westminster City Council was concerned about the potential effect of conversations and other outdoor activity in an otherwise relatively quiet rear courtyard environment.

Inspector A Caines concluded that the applicant’s detailed acoustic assessment and the Council environmental health officer’s lack of objection supported the proposed increase. The Westminster roof terrace appeal is a useful test of evidence, existing permission and operational safeguards in an application to vary planning conditions.

Westminster roof terrace appeal: the new operating limits

The appeal concerned a section 73 application, reference 25/07543/FULL, to vary conditions attached to permission 24/08150/FULL, issued on 16th April 2025. That earlier consent permitted alterations and refurbishment of Belgrave House, including use of the rear fifth-floor terrace as an amenity for office occupiers.

Conditions 10 and 11 had restricted the rear terrace to weekday use between 8am and 7pm and a maximum of 60 people. The appellant sought permission for use between 7am and 10.30pm from Monday to Friday, with up to 120 people at any one time. Use on Saturdays and Sundays remained prohibited.

The Inspector allowed the appeal under section 78 and issued a new planning permission with substituted conditions. The revised condition 10 permits use between 07:00 and 22:30 on weekdays only; condition 11 caps simultaneous occupation at 120 people. That is a capacity ceiling, not a guaranteed right to operate without complying with the other controls.

A busy street does not mean a noisy rear courtyard

Belgrave House faces Buckingham Palace Road, where buses, traffic and commercial activity create a busy city-centre soundscape. Its rear elevation is different. It faces Eccleston Place and nearby flats, including residential accommodation at 55 Ebury Street.

The nearest residential windows are approximately 15 metres from the roof terrace. The Inspector acknowledged that the enclosed rear setting was quieter and more sensitive to noise than the building’s principal frontage. It would therefore have been misleading to rely solely on background measurements taken beside the main road.

The Westminster roof terrace appeal turned on the additional noise likely to arise from allowing more people onto an already approved terrace for a longer weekday period. The Inspector was not being asked to determine whether a new terrace should exist at all. That baseline shaped the assessment.

What the acoustic assessment actually demonstrated

The applicant produced a specific acoustic assessment dealing with the proposed changes. It modelled the likely effect of conversation and associated activity from up to 120 terrace users on nearby residential receptors in the quieter rear environment.

Rather than assuming a typical light-use day, the modelling adopted a deliberately conservative scenario: the terrace was occupied at its maximum capacity and a substantial proportion of people were assumed to be speaking at the same time. The assessment predicted only a very small change in noise levels, with no significant adverse effect.

The Council’s Environmental Health Officer reviewed that material, raised no objection and regarded the proposal as unlikely to cause disturbance. A further technical note on appeal explained the methodology. No competing technical assessment undermined its conclusions. The Inspector therefore found the evidence persuasive despite recognising that conversations may still be audible from neighbouring flats.

Noise can be intrusive even when modelling predicts little harm

The Inspector did not treat decibel calculations as the only consideration. Speech, laughter and human activity can be more noticeable than some continuous mechanical noise. Residents also raised understandable concerns about proximity, the number of users and the prospect of activity late in the evening.

Nevertheless, the planning judgment required a distinction between being aware of terrace activity and experiencing an unacceptable change in living conditions. The already permitted terrace was the baseline. The decision asked whether the additional hours and people would create materially harmful effects beyond that established position.

The Westminster roof terrace appeal illustrates why evidence must match the sensitive receptors and worst realistic operating scenario. Without a convincing technical challenge or site-specific reason to reject the appellant’s modelling, the Inspector was not persuaded by the Council’s concern that 120 people would be inherently intrusive.

Why the St Martin’s Lane comparison did not decide it

Westminster relied in part on an earlier appeal concerning a roof terrace at St Martin’s Lane, reference APP/X5990/W/17/3172739. That decision had highlighted the inherent uncertainty involved in predicting human noise. The Inspector accepted that such modelling depends on assumptions, but rejected the suggestion that predictive work is automatically unreliable.

Here, the appellant used recognised methodology, considered the neighbours most likely to be affected and tested a busy terrace scenario. The Council’s own specialist had reviewed the assessment. Other local roof terrace conditions were considered but did not establish a fixed rule about suitable opening hours.

The decision is therefore not a general precedent for all commercial terraces to operate until 10.30pm. Acoustic context, the building’s surroundings, the existing planning baseline and the quality of proposed management arrangements can all lead to different outcomes.

Management conditions remain central to the permission

Several safeguards remain. The terrace may only be used by office occupants, not as a public bar or general events venue. Live or amplified music is prohibited. Structures including canopies and trellises are restricted, and the approved planting and screening arrangements remain relevant.

Condition 19 requires a detailed Operational Management Plan before the terrace is used. It must address access, opening hours, capacity, smoking and noise control. The approved plan must then be followed unless revised with the local planning authority’s written agreement.

The Inspector also adjusted condition 12 to match lighting to the new weekday hours, with external terrace lights switched off outside 7am to 10.30pm except for emergency or maintenance purposes. The revised hours therefore sit within a broader package of management rather than operating independently of it.

Section 73 creates a new permission, not extra time

Section 73 of the Town and Country Planning Act 1990 enables a new planning permission to be granted subject to different conditions. It does not automatically extend the period for commencing the originally authorised development or extinguish the first permission. This is an important distinction for landlords and developers varying consented schemes.

The Inspector reimposed the surviving conditions from the 2025 permission, taking account of a non-material amendment, reference 25/05905/NMA. A final condition requires commencement by 16th April 2028, retaining the original development deadline rather than awarding a new three-year period.

The appeal also considered the current development plan. The Inspector applied the London Plan 2021 and the adopted City of Westminster City Plan 2026, finding compliance with London Plan Policy D14 and Westminster policies 7 and 37 on environmental quality and residential living conditions. This reinforces the importance of checking policy changes between initial permission and a later variation application.

Heritage and privacy objections did not alter the result

Several heritage assets lie nearby, including listed buildings on Buckingham Palace Road, Victoria Station and the Grosvenor Hotel. However, the appeal proposed no physical alteration to the existing approved terrace. The Inspector found no evidence that revising the operating conditions would harm the significance or setting of those assets.

Residents also raised overlooking and privacy concerns. Screening and landscaping already formed part of the consented terrace arrangement and were not being changed. The Inspector found no persuasive evidence that the longer hours or additional users would create materially greater overlooking than had already been authorised.

Those findings were tied closely to the narrow scope of the appeal. A different proposal involving new deck areas, changed sightlines, intensified public use or inadequate screening would require its own assessment rather than relying on the result at Belgrave House.

Lessons for planning condition appeals

The practical lesson is to frame a section 73 proposal around the change actually sought and show its effect against the permitted baseline. Commission noise evidence that addresses nearby bedrooms and courtyards, not merely the noisiest side of the building. Explain occupancy assumptions, control measures and management responsibility with enough precision to be enforceable.

Before appealing, applicants should test whether any specialist consultee objections remain and whether a management plan can mitigate the identified effects. Councils, meanwhile, need more than a general concern about a possible nuisance where a robust assessment and their own environmental health advice point in the opposite direction.

The full decision is available through the Planning Inspectorate appeal record and Appealbase decision text. Planning Geek also explains how an amended permission may affect Community Infrastructure Levy under section 73. This is an Inspector’s appeal decision, not a court judgment or blanket relaxation of Westminster’s noise policy.