The Agent of Change principle – that the ‘agent’ person introducing a new land use is responsible for managing the impact of that change – has been part of NPPF policy since 2018, driven by debates around noise-sensitive residential development near noise producing uses (such as theatres and nightclubs).
The principle has been applied more widely in practice, including in large-scale housing schemes adjacent to industrial uses, with solutions found through conditions and S106 obligations, such as the Muckingford Road, Essex 800-home appeal scheme.
This appeal decision related to a s73A application to remove a planning condition regulating the noise of a generator required to ventilate hen houses.
A poultry and sheep business was established on the site in 2015. Permission for various agricultural buildings was obtained in 2016, and Wychavon District Council’s advice at that point was that planning permission was not required for moveable hen houses, and so no permission was sought for that element of the business. The hen houses required ventilation, and in accordance with the relevant legislation and to ensure the health of the birds if the main electricity supply was disrupted, a generator was purchased in 2015 and brought on site in 2016.
In 2020, the Council made the appellant aware that changes in case law meant that permission may be required for the moveable hen houses. The appellant made an application partly retrospectively, and partly for new development.
In the meantime, planning permission was granted in 2021 for a live work unit adjacent to the site, unconnected to the farm operations.
Planning permission was granted pursuant to the part retrospective, part new application in 2022 for agricultural buildings, including grain silos, chicken sheds and moveable hen houses. The permission was subject to a condition that the new buildings could not be used for longer than 9 months (from the date of the permission), unless a noise attenuation scheme ensured that the generators provided as part of the development were not audible on the north west boundary. The reason given for this condition was to protect residential amenity and prevent unacceptable noise pollution. The appellant appealed the imposition of this condition, and it was heard at a hearing in March 2025.
The Inspector considered the necessity, relevance to planning and whether defects in the condition could be rectified, before concluding that imposing the condition would be contrary to the ‘agent for change’ principle set out at paragraph 200 of the National Planning Policy Framework. The agent of change principle states existing businesses should not have unreasonable restrictions placed upon them as a result of development permitted after they were established. If proposed development would be significantly adversely impacted by existing operations, the proposed development should include adequate mitigation.
Here, although there were some changes proposed as part of the application, including the generator being in a fixed location rather than being mobile, there had been an established use of a generator prior to the application for the live work unit being submitted. Therefore, the live work unit was the agent of change and the impact of existing operations and the potential need for mitigation should have been considered as part of that application, not imposed on the existing business. The Inspector found the agent of change principle had been misapplied and placed an unreasonable burden on the existing enterprise.
The crucial element of agent of change debates is whether the new (sensitive) use would require the existing use to be subject to onerous controls. As part of the decision, the Inspector considered whether the requirement the generator be “inaudible” at the property boundary was sufficiently precise and enforceable, concluding that it was, before going on to consider whether the condition was reasonable in all other respects. The Council conceded that the consequence of not being able to use any part of the structure permitted as part of the permission was unreasonable, and further that the requirement that the generator be inaudible at the property boundary, rather than at the receptor, was unreasonable – therefore, a condition containing other, reasonable, restrictions may have been acceptable. In addition, the agent of change principle was misapplied, and placed unreasonable restrictions on the existing enterprise. The appeal decision clearly sets out the agent of change principle, providing a helpful application of the principles and impact on existing businesses.
