Mark Child analyses a recent Court of Appeal judgment involving a national park authority and what it means for sites with multiple planning permissions and the practice of ‘drop-in’ permissions.
The case of Hillside Parks Limited v Snowdonia National Park Authority  EWCA Civ 1440 concerned a 28-acre site that had previously received planning permission in 1967 for a development of 401 dwellings, which included reference to a ‘Master Plan’ (1967 Permission). The 1967 permission was implemented with the construction of a handful of homes. Further permissions and departures from the Master Plan were then granted between 1967 and 1973.
A dispute arose between the local planning authority and the landowner at the time in 1985, with the local planning authority refusing to accept that the 1967 Permission was still valid. At the time of trial the local planning authority agreed that the 1967 Permission was in fact lawful and the court ruled that the development permitted by the permission had begun and so could be lawfully completed at any time in the future (1985 Judgment).
Hillside Parks Limited (Hillside) acquired the site in 1988 and Snowdonia National Park Authority (Snowdonia) became the local planning authority in 1996. A number of departures from the Master Plan were approved by Snowdonia, who then contacted Hillside in 2017 stating that the 1967 Permission could no longer be implemented because developments carried out in accordance with later planning permissions rendered it impossible to implement the original Master Plan. As a result Snowdonia required that all works on site be stopped until the planning situation had been regularised. Hillside therefore sought declarations from the High Court, including that Snowdonia was still bound by the 1985 Judgment and that the 1967 Permission could be relied upon to completion, save insofar as development had been carried out pursuant to another permission.
Court of Appeal Judgment
In dismissing the appeal, the Court of Appeal held that the High Court had rightly decided that it had become impossible, due to the events since 1987, for the 1967 Permission to be implemented in full. That was despite the fact that many of the homes shown on the Master Plan could still be constructed in accordance with that plan. In support of this conclusion, it cited the need for the public and future purchasers to be clear under which permission a property had/ was being developed, not least because permissions run with the land.
The Court of Appeal accepted that the application of the Pilkington principle in the High Court was correct: the implementation of later permissions had made physically impossible the continuation of the 1967 Master Plan scheme. The factual position was critical to that judgment. Whereas in Pilkington development ‘overwriting’ the allotment garden of a previously-consented (and implemented) residential scheme was enough to rule out reversion to the previous consent, in Hillside the incompatibility of the road layout with the previous consent was enough to tip the balance. The Court of Appeal made clear that such impossibility must be considered against delivery of the full underlying permission (Sage v Secretary of State for the Environment  UKHL 22). Endorsing Singh v Secretary of State for Communities and Local Government and Another  EWHC 1621 (Admin), for a development to be lawful it must be carried out “fully in accordance with any final permission under which it is done”. Hickinbottom J in Singh stated that if a development cannot be completed because of the impact of other operations under a different planning permission, the subsequent development as a whole would be unlawful.
The Court of Appeal deliberately declined to address whether “subsequent development as a whole” should be interpreted as any development carried out under the permission to date was unlawful or only the later development. In the interests of certainty the latter interpretation should be favoured, consistent with Pilkington, but this will require confirmation from the courts.
A word of warning
“Drop-in” applications are commonly used to provide permission where a part(s) of the permitted development needs to be changed as it can often create flexibility for the developer (especially in a multi-phased scheme where market conditions may change). Following Hillside, there has been some comment suggesting that implementing “drop-in” applications will prevent reliance on the original application where the “drop-in” application makes it impossible to complete the original application as permitted. In some historic consents that may be true. The Hillside judgment confirms that the factual position matters, though. Major applications and consents can readily be designed and structured in a way that allows for future changes or “drop in” applications without that effect, allowing sites to be developed out under separate consents if necessary. Alternatively section 73 applications can be used to deal with the drop in element of a site while keeping the balance of the consent intact, either within the section 73 consent or by drafting the conditions/obligations in a way that leaves the underlying parent consent still capable of implementation.
Applicants seeking significant changes beyond the scope of a s.73 application may have to make them via a standalone “drop in” alongside a s.73 application re-drawing the conditions from the original permission so that it can (in the guise of the s.73 permission) continue being implemented if there are outstanding works to be completed (one such condition will be the drawing references).
Applicants should therefore consider carefully not only its approach to an original planning application, but also to any subsequent “drop-in” applications. As Hillside shows mistakes can be both costly and time consuming.
Applicants should also carefully consider whether their original description of development is sufficiently flexible following Finney v Welsh Ministers  EWCA Civ 1868, as this can only be amended through a non-material amendment. Ideally the description should be sufficiently broad in order to allow for later “drop-in” or s.73 applications without causing further procedural difficulties.
 assuming that the local planning authority will not accept a non-material amendment under s.96A