Proposed demolition of existing garage and erection of detached outbuilding/studio without complying with a condition attached to planning permission Ref DC/17/1129, dated 21 July 2017

Appeal Decision Site visit made on 9 June 2026 by Thomas Courtney BA(Hons) MA MRTPI an Inspector appointed by the Secretary of State Decision date: 3rd July 2026 Appeal Ref: 6005580 Chennells Brook House, North Heath Lane, Horsham, West Sussex RH12 5PJ • The appeal is made under section 78 of the Town and Country Planning Act 1990 (as amended) against a refusal to grant planning permission under section 73 of the Town and Country Planning Act 1990 (as amended) for the development of land without complying with conditions subject to which a previous planning permission was granted. • The appeal is made by Mr David Algar (Building Designs) against the decision of Horsham District Council. • The application Ref is DC/25/1620. • The application sought planning permission for the proposed demolition of existing garage and erection of detached outbuilding/studio without complying with a condition attached to planning permission Ref DC/17/1129, dated 21 July 2017. • The condition in dispute is No 5 which states that: The detached outbuilding/studio building hereby permitted shall be used solely for purposes ancillary to the occupation and enjoyment of the main dwellinghouse at Chennells Brook House North Heath Lane Horsham and shall not be occupied as an independent planning unit of residential accommodation or used for any commercial/business purposes. • The reason given for the condition is: The use of this building as an independent residential unit or for commercial/business purposes would be contrary to Policy 33 of the Horsham District Planning Framework (2015). Decision 1. The appeal is dismissed. Main Issue 2. The main issue is whether the proposed variation of Condition 5 would provide appropriate control over the ancillary use and occupation of the building. Reasons 3. The appeal site comprises a detached dwelling set within a spacious plot on the western side of North Heath Lane, Horsham. The outbuilding is a detached structure positioned towards the frontage of the site, separate from the principal dwelling but within its residential curtilage. It has the appearance of a small barn- like building and is accessed from the shared driveway serving the main house. There is a dedicated parking space next to the outbuilding, together with surrounding planting and patio area. 4. Condition 5 requires the outbuilding to be used solely for purposes ancillary to the occupation and enjoyment of the main dwellinghouse and prevents its occupation as an independent planning unit of residential accommodation or use for commercial/business purposes. The condition therefore has two related functions. It links the use of the building to the host dwelling and expressly prevents a form of occupation that would be independent of it. Appeal Decision 6005580 2 5. Given the scale, detached position and residential character of the outbuilding, I consider that Condition 5 serves a clear planning purpose. It is relevant to planning and to the development permitted, and it is sufficiently precise in identifying the nature of the use that is permitted and the form of occupation that is not. It is also reasonable, as it does not prevent the incidental use of the building associated with the main house. It ensures that the building remains part of the residential use of Chennells Brook House and does not become occupied independently from it. 6. The proposed variation would retain the requirement that the building be used for purposes ancillary to the occupation and enjoyment of the main dwellinghouse. However, it would remove the express restriction preventing occupation as an independent planning unit of residential accommodation. It would instead prevent the building from being separated or sold off as an independent planning unit. 7. I acknowledge that planning control is concerned with land use consequences rather than the personal relationship between occupiers. I also accept that a tenancy agreement, or occupation by persons who are not family members, would not of itself create a separate planning unit. Whether accommodation has become independent from the host dwelling is a matter of fact and degree, having regard to the physical and functional relationship between the buildings and their occupants. 8. However, those points do not demonstrate that the existing restriction is unnecessary or excessive. The issue is not whether future occupants would be friends, family members or tenants. The issue is whether the proposed wording would continue to provide effective control over the occupation of a detached building capable of supporting a significant degree of independent residential living. 9. During my site visit, I observed that the outbuilding contains facilities which appear capable of supporting day-to-day residential occupation, including a kitchen, bathroom and living area at ground floor level, together with a dedicated parking space and private outside amenity space. The plans submitted with the appeal provide only limited information regarding the current internal layout, although they show a WC and stairs. Nevertheless, my observations indicate that the building is capable of being occupied with a considerable degree of independence from the principal dwelling. 10. In that context, the removal of the express prohibition on occupation as an independent planning unit would materially weaken the control imposed by Condition 5 without providing an equivalent mechanism for ensuring that the building remains occupied in a manner that is part and parcel of the residential use of Chennels Brook House. The proposed replacement wording would not provide an equivalent safeguard, because it would focus on separation or sale rather than on how the building is actually occupied. Whilst ancillary use or occupation may encompass a range of living arrangements, it must remain subordinate to and functionally connected with the occupation and enjoyment of the main dwellinghouse. I have not been shown that the occupation of the outbuilding would remain sufficiently integrated with the main dwelling, or that the revised wording would adequately secure that outcome. 11. The appellant refers to the fact that services and access are shared with the main dwelling. These are relevant considerations and point to a degree of physical connection. However, the evidence before me does not demonstrate a functional Appeal Decision 6005580 3 connection sufficient to justify removing the existing restriction. In particular, there is limited evidence as to how the occupiers of the outbuilding would live as part of the household occupying the main dwelling, or how the shared facilities would operate in practice so as to ensure that the accommodation remained genuinely ancillary. There would be no control for example that would prevent occupiers of the building from receiving services such as electricity and gas from providers independently. 12. The Council also raises concerns regarding the effect of the proposal on character and appearance and on living conditions. I am mindful that no external alterations are proposed and the building already exists. I therefore do not find that the appeal proposal would, in itself, result in additional visual harm merely by reason of a change to the wording of the condition. However, the concerns do underline the importance of ensuring that the outbuilding does not become used in a way materially different from the ancillary accommodation that was permitted. A self- contained and independently occupied residential unit may raise considerations relating to the adequacy of accommodation, layout, private amenity space, parking, activity and its relationship with the host dwelling which were not before the Council when the outbuilding was permitted as ancillary accommodation. Those matters have not been satisfactorily demonstrated to be acceptable in the context of independently occupied residential accommodation. 13. For these reasons, I am not satisfied that the proposed variation would provide appropriate or effective control over the future occupation of the outbuilding. The existing condition remains necessary, relevant, enforceable, precise and reasonable, and the proposed wording would fail to secure the planning purpose that the condition was imposed to achieve. 14. Accordingly, I conclude that the proposed variation of the condition would not satisfy the tests for planning conditions set out in paragraph 57 of the National Planning Policy Framework. It would also conflict with Policies 32 and 33 of the Horsham District Planning Framework (2015) insofar as they seek to ensure that development is of a high standard of design and layout and avoids unacceptable harm to the amenity of occupiers. Other Matters 15. I have had regard to the appellant's submission regarding the efficient use of land in a sustainable urban location. However, the appeal does not concern the principle of the outbuilding's occupation, which is already authorised by the existing permission. Rather, it concerns whether the express restriction requiring that occupation to remain ancillary to the main dwelling should be varied. Accordingly, this consideration attracts limited weight. Conclusion 16. The proposal conflicts with the development plan and the material considerations do not indicate that the appeal should be decided other than in accordance with it. 17. For the reasons given above the appeal should be dismissed. Thomas Courtney INSPECTOR