Rear garden annexe building

Appeal Decision Site visit made on 13 January 2026 by L Gardner MRTPI an Inspector appointed by the Secretary of State Decision date: 19 January 2026 Appeal Ref: 6001088 40 Greenacres Avenue, Ickenham, Hillingdon UB10 8HH • The appeal is made under section 78 of the Town and Country Planning Act 1990 (as amended) against a refusal to grant planning permission. • The appeal is made by Trevor Vince against the decision of the Council of the London Borough of Hillingdon. • The application Ref is 66743/APP/2025/1777. • The development proposed is rear garden annexe building. Decision 1. The appeal is allowed and planning permission is granted for rear garden annexe building at 40 Greenacres Avenue, Ickenham, Hillingdon UB10 8HH in accordance with the terms of the application, Ref 66743/APP/2025/1777, subject to the following conditions: 1) The development hereby permitted shall begin not later than three years from the date of this decision. 2) The development hereby permitted shall be carried out in accordance with drawing nos 2512-PL-L&B; 2512-PL-101 Rev. A; 2512-PL-102 Rev. A; and 2512-PL-103. 3) The external surfaces of the development hereby permitted shall be constructed in the materials shown on plan no. 2512-PL-103. Main Issues 2. The main issues are: • whether or not the proposed annexe building would comprise a separate self-contained residential unit; • the effect of the proposal on the character and appearance of the area; and • the effect of the proposal on the living conditions of neighbouring occupiers, with particular regard to noise and disturbance. Reasons Whether self-contained dwelling 3. Policy DMHD 2 of the Hillingdon Local Plan Part 2 (HLP) (2020) relates to outbuildings setting out several criteria for proposals to meet. These include that the use of the outbuilding shall be for a purpose incidental to the enjoyment of the dwellinghouse and not capable for use as independent residential accommodation. Appeal Decision 6001088 2 The policy goes on to state that primary living accommodation such as a bedroom, bathroom, or kitchen will not be permitted. The proposed annexe building would have primary living accommodation including a bedroom, bathroom and kitchen facilities. In this respect, it would conflict with Policy DMHD 2 of the HLP. 4. Gravesham BC v SSE & O’Brien [1983] JPL 306 identified the distinctive characteristic of a dwellinghouse was its ability to afford, to those who used it, the facilities required for day-to-day private domestic existence. However, the judge in Uttlesford DC v SSE & White [1992] JPL 171 considered that, even if the accommodation provided facilities for independent day-to-day living, it would not necessarily become a separate planning unit from the main dwellinghouse. In each case, it would be a matter of fact and degree. As per Burdle v SSE [1972] 3 All ER 240, a consideration of physical and functional connection is a useful tool for assessment. 5. The building would not be physically connected to the main dwellinghouse and given the positioning of the appeal site at a corner plot, it would be physically possible to create two separate vehicular and pedestrian accesses. However, the building would share a close spatial relationship to the main dwellinghouse with its entrance doors facing into a shared garden area, which would be impractical to separate. 6. Moreover, the appellant has outlined a strong functional connection between the proposed annexe building and the main dwellinghouse. I understand that the intended use of the building is for occupation by a family member of the main dwellinghouse to assist with growing care needs. It is presented that living activity such as the consumption of meals would be as a single family unit in the main dwellinghouse. Services such as electricity, gas and water would also be shared with the main dwellinghouse. 7. Taking all of the above factors into account, I am satisfied that the proposed annexe building would form part of ordinary living accommodation and that all occupiers would be regarded as a single household. On this basis, the proposed annexe building would not comprise a separate self-contained residential unit. 8. Whilst I have identified conflict with Policy DMHD 2 of the HLP in relation to the internal facilities of the building, given my conclusions that the building would not operate as a separate residential unit, I find that this particular scheme would not undermine the overall objectives of this policy. 9. On the basis of my findings, I find little relevance to Policies DMH 6, DMHB 16 or DMHB 18 of the HLP and Policy D6 of the London Plan (LP) (2021) which relate collectively to garden and backland development, housing quality and standards as well as standards for private outdoor amenity space. Policy D1 of the LP is also of limited relevance to the appeal proposal before me given that it relates to a more strategic approach to planning for growth. Character and appearance 10. Policy DMHB 11 of the HLP relates to the design of new development requiring all development, including new buildings, to be designed to the highest standards taking into account the surrounding area. Policy DMHB 12 goes on to require development to be well integrated with the surrounding area. Policy D4 of the LP relates partly to maintaining design quality. Appeal Decision 6001088 3 11. The appeal site occupies a corner plot in a primarily residential area. Thus, whilst the proposed annexe building would be positioned at the rear of the garden, it would still be visible in the wider street scene. Nevertheless, the building would be modest in its scale with a footprint which would be subordinate to the size of the main dwellinghouse. There are other similarly scaled outbuildings in the wider area (including at the adjacent plot at 42 Greenacres Avenue). 12. Despite reference within the decision notice to the character and appearance of the area, the Council has accepted within its officer report that the building would not detract from the visual amenities of the surrounding area. I see no reason to take a different judgement on this matter and have therefore identified no direct conflict with Policy D4 of the LP or Policies DMHB 11 and DMHB 12 of the HLP. Living conditions 13. Policy D3 of the LP refers in part to a design led approach requiring development proposals to deliver appropriate amenity and help prevent or mitigate the impacts of noise. The Council is of the view that the use of the proposed building as a separate dwellinghouse would give rise to noise and general disturbance. 14. However, I have identified above that the proposal would form part of the living accommodation for the main dwellinghouse. The comings and goings associated with the proposal would be imperceivable in the residential context of the appeal site. I have therefore identified no harm to the living conditions of neighbouring occupiers, with particular regard to noise and disturbance and no direct conflict with Policy D3 of the LP. Conditions 15. In the interests of certainty and clarity, I have imposed the standard conditions relating to the commencement of development as well as the approved plans. A condition requiring the building to be constructed in the materials stated on the submitted plans is necessary in order to maintain the character and appearance of the area. 16. The description of development is explicit that the building would be for use as an annexe. If the building were not to be used for such a purpose, or if there is a material change of use in the future to create a separate dwelling, then a separate grant of planning permission would be required, and the building would be at risk of enforcement action if such permission is not granted. As such, a condition controlling the use of the building is not necessary. Conclusion 17. Notwithstanding the minor conflict with Policy DMHD 2, in the absence of identifiable harm, the proposal would comply with the development plan when read as a whole. There are no material considerations which indicate a decision should be made other than in accordance with the development plan. I therefore conclude that the appeal should be allowed. L Gardner INSPECTOR