The Hillside to Die Upon?

How the Dennis case has closed down one strategy to address Hillside case restrictions on amendments to planning permissions.

I am a solicitor. I love complexity and my livelihood is, to a large extent, dependent upon it. I am also a planning solicitor. Planning should be about pragmatism and practicality. One of the first things I learnt as a trainee solicitor was that pragmatism and practicality should always trump complexity. During my early career, flaws in the legislation were apparent but the leading authorities seemed to come down on the side of pragmatism when dealing with amendments to permitted developments; there was much flexibility for both s73 applications and drop-in permissions. Changes could easily be secured without too much fuss as, if the planners were happy as to the planning merits of the proposals, then usually there would be no issue.

Wet Finishing Works in 2017 reinforced the pragmatic and practical approach in the context of s73 permissions but then came Finney in 2019 and things became more difficult for the s73 route. Planning solicitors up and down the country were devising mechanisms to enable permissions to be amended under s73 within restricted confines but drop-in permissions were left unscathed.

Then came the Supreme Court’s decision in Hillside [2022] UKSC 30 in 2022 which severely restricted the use of drop-in permissions. Once again, planning solicitors up and down the country were devising mechanisms, but this time to enable lawful drop in permissions to be secured without jeopardising the remainder of the scheme. Our previous updates on the previously understood implications of the decision are here:

Now cometh Dennis [2024] EWHC 57 (Admin) and one such mechanism has been closed down. In this case, the developer and local authority defendant sought to rely on the conclusions in Hillside that a clear express provision in a planning permission making it severable could enable a permission to be construed as still authorising further development following the grant and implementation of a drop-in permission which would ordinarily make compliance with the original permission physically impossible. Basically, drop-in permissions would not prevent the subsequent build out of the original permission if the original permission was expressly stated to be severable.

The facts in Dennis were that outline permission was granted for a phased redevelopment and regeneration scheme. A drop in detailed planning application was made for one of the early phases that would be inconsistent with the outline permission and so, following Hillside, would render the remaining phases unable to be lawfully built under the outline unless it was concluded that this phase could be severed from the outline permission.

The strategy pursued by the developer and local authority involved using a s96A application to simply insert “severable” into the description of development, coupled with the assertion that the outline permission, being phased, was always “severable”; the s96A was simply to confirm the position explicitly on the face of the consent.

Somewhat surprisingly the parties agreed that, if the outline permission was not severable, then the s96A application would be unlawful, which essentially meant the Council and the developer conceded, without arguing the point, that the change that in that circumstance was “material” and, therefore, outside of the scope of a s96A non-material amendment application; I think it would of at least be worth pursuing an argument that making a phased outline permission severable would not be material but, for whatever reason, this line wasn’t taken by the Council or the developer.

The outcome was that the court concluded that the outline permission was not severable (phasing was not sufficient alone to make it severable) and that it could not be made severable by simply inserting the word “severable” into the description of development. Furthermore, in light of the concession made by the Council and developer, the judge agreed that the change purportedly made by the s96A was material and, therefore, outside of the powers in s96A. The s96A consent was quashed. The drop-in permission, if implemented, would make it unlawful to build the remainder of the development under the original outline permission.

Before getting into the implications, it is worthwhile taking a few steps backwards to consider what the driving factors are here.

Pretty much every large scheme evolves as it progresses through its delivery. This is often a result of detailed design issues, unforeseen (and unforeseeable) technical issues, and/or economic and market conditions. It is very naïve and unrealistic to expect that large developments should always be, or even could always be, delivered in exact accordance with the planning permission as originally granted. As such, the planning system needs to be able to respond appropriately to necessitated changes to developments throughout its delivery.

Clearly, there should not be free reign to amend developments at will of the developer without an appropriate process that enables the planning merit implications of the amendments to be considered as well as enabling interested parties, including members of the public, to comment on the implications of the amended development. On this point, other than s96A applications which, of course, should only lead to non-material changes, the usual mechanisms for amending developments, e.g. s73 permissions or drop-in permissions, are subject to appropriate processes that do enable the planning merits to be considered and for interested parties to comment on the proposed amendments. In this regard, it is, in my view, wholly without merit and no more than cheap “developer vs the community” rhetoric to suggest that amendments to developments in such circumstances are somehow contrary to the interests of the local community.

It is in this context that mechanisms to ensure that developments can be appropriately and lawfully amended are required. The mechanism used in Dennis did not provide such a solution.

So, what are the implications of Dennis, coupled with Hillside, for amending schemes by drop-in permissions? The key ones are:

  1. Full and outline permissions cannot be assumed to be severable and will not be considered severable unless there is express provision in the permission itself;
  2. Phasing alone is not sufficient to demonstrate that the permission is severable;
  3. Existing full and outline permissions cannot be made severable by simply changing the description of development to include the word “severable” by way of a s96A application. Arguments could still be made in the future that making a development severable would not be material and so suitable for a s96A application but this must involve more than adding “severable” into the description. However, as the developer and Council will be for looking for a safe solution to use, significant caution should be used in choosing a s96A application to make a planning permission severable;
  4. Drop-in permissions for a development that is being built out pursuant to an existing full or outline permission are lawful but you need to be very careful not to lose the ability to lawfully build out the rest of that permission;
  5. Any development which is being built pursuant to a permission which is not expressly stated to be severable, and for which a drop-in permission has been granted and implemented during its build, will have potentially lost the benefit of the original permission meaning it can no longer be lawfully continued without further permissions. I suspect there will be plenty of examples of such developments, especially large, multi-developer schemes;
  6. Be careful with establishing that the outline permission is severable; commentary in Dennis suggests that you could lose the benefit of later parts of the development if the permission is severable and those parts are not implemented or reserved matters approvals are obtained within the same timeframes as the whole of the permission i.e. you can’t assume that implementation of the permission will have the effect of legally implementing all severable parts of the permission;
  7. The above two implications are of considerable concern as they could prevent the lawful build out of schemes that are in the course of construction where drop-in permissions have been granted or where the original permission is concluded to be severable but later parts were not implemented in accordance with the original time limit condition;
  8. The practical implication that may be the safest course in many circumstances is to submit a s73 application to amend the original planning permission to maintain overall consistency in the design of the development at the same time as submitting the drop-in application so that the 2 applications can be considered and determined together;
  9. However, in our experience, developers will generally view this as unwelcome in that the s73 application could re-open a wide range of planning issues for further consideration that were determined on the original permission for the overall development, including liabilities under any associated S106 Planning Agreement. Furthermore, a change to the S106 Planning Agreement on a large site a number of years after it was originally signed may require the agreement of third parties;
  10. It seems inevitable that the consequences of the recent case law will be that the delivery of some developments will suffer additional constraints, delays and costs that will be unhelpful, including additional judicial review risks.

At the start of this article, I felt almost nostalgic about the pragmatism and flexibility previously applied in the planning system. Over the last few years, it has become much more complicated to secure amendments to developments with the benefit of existing planning permissions. The flaws and gaps in the legislation have been clarified by the courts in favour of less pragmatism and more complexity. This is not the court’s fault but very much a failure of the Government to address these known issues in revised legislation to satisfactorily resolve the issue. It has had the opportunity to do so but has neglected to it.

Throw in other complicating factors, such as CIL, and amending permissions starts to feel like a labyrinth that Daedalus would be proud of. Where is Ariadne and her ball of red thread when needed? 

Freeths did not help Theseus escape the labyrinth but, until the legislative position is fixed, we can provide the metaphorical ball of red thread to successfully guide you through the complexity of amending existing permissions and pursuing drop-in application, whilst avoiding these issues being the Hillside which your development dies upon.

To discuss anything covered in this article please get in touch with Chris May.

Get in touch

The content of this page is a summary of the law in force at the date of publication and is not exhaustive, nor does it contain definitive advice. Specialist legal advice should be sought in relation to any queries that may arise.

Get in touch

Contact us today

Whatever your legal needs, our wide ranging expertise is here to support you and your business, so let’s start your legal journey today and get you in touch with the right lawyer to get you started.


Get in touch

For general enquiries, please complete this form and we will direct your message to the most appropriate person.