Hillside Parks

While Hillside is in many respects a product of its own "extreme" facts – in terms of the age of the original masterplan consent and what had happened on the site since - it nevertheless has implications for schemes involving drop-in applications or overlapping permissions. However, it is important to bear in mind that this is not a case about the validity of drop-ins but rather the legal effect of implementing subsequent permissions on an existing wider permission. There are two aspects to this:

1. The effect on development already carried out under the existing permission – as noted above, the judgment helpfully confirms that the lawfulness of existing development would be unaffected by the implementation of an inconsistent permission. On the contrary, the judgment means that an inconsistent drop-in or overlapping permission does not adversely affect development already carried out. This is fine if the development that has been carried out is completed development so that the planning permission does not need to be relied on further. 
2. The effect on the ability to carry out further development under the existing permission - here the judgment relies on the Pilkington principle to conclude that the ability to rely on the original consent will be lost where it becomes physically impossible to carry out the consented development because of the implemented later permission. While this means that the Supreme Court's decision is based on existing law, and nothing should really have changed, it is this part of the decision that has practical implications due to the gap between the law on the variation of consented schemes and well established industry practice on the use of drop-in applications. In particular, where construction of a wider site is underway, implementation of an incompatible drop-in permission must be avoided to stop partially completed development from potentially becoming incapable of lawful completion unless a further permission is obtained.

Where does all this leave drop-ins? The answer is it's complicated and each scheme will require an assessment of whether a drop-in is the appropriate process to effect a scheme change or whether another procedure, such as a section 73 or 96A application is more appropriate. But what we can say with certainty is that Hillside has not killed off the drop-in and it has given us a few key principles to bear in mind and raised a few questions that require further thought.

As we mention above, if there is no intention to carry out any further development under the existing consent, there is no need to be concerned about the drop-in permission cancelling the earlier permission. However, for drop-ins where further development is still to be carried out under an existing consent, care will be needed to ensure that the applicant does not inadvertently lose the benefit of any existing consent.

The appellant in Hillside ran an argument that the later permissions should be treated as variations of the original permission. The Court resoundly rejected that argument and added that "there is no reason why an approved development scheme cannot be modified by an appropriately framed additional planning permission which covers the whole site and includes the necessary modifications" (our emphasis). The Court added that "ordinarily it [the variation application] would have to be accompanied by a plan which showed how the proposed new permission incorporated the changes indicated into a coherent design for the whole site". However, having to draw your redline around the entire site does present additional considerations because the drop-in becomes, in effect, a brand new planning application for the whole site with implications for the application fee, environmental impact assessment and section 106 agreement particularly where there are multiple landowners. In those circumstances, an application under section 73 to "slot out" development consented on part of the site to enable new development to be slotted or dropped in to just that part could be considered.

We referred above to the Court's rejection of the appellant's argument that, for a multi-unit development, each element of the masterplan is a freestanding permission and the ability to develop each element does not depend on whether it is still physically possible to develop other parts of the site in accordance with the original permission. The court said that, in the absence of "some clear contrary intention", it is not correct to interpret such as permission as severable. This raises the question what is a severable permission.  In our view, it means more than a planning condition that provides for the development to come forward in phases and to avoid a risk of challenge it would be sensible to provide for severability in the description of development.