Supreme Court issues landmark judgment in Hillside Parks case greatly affecting planning & real estate practice

It has been common on development sites (particularly large ones) to obtain an original planning permission and then pursue changes for part of the site, by lodging a subsequent planning application to “drop-in” alternative development submitted as a fresh, separate application.

The Supreme Court has held that generally the implementation of one of these subsequent “drop-in” permissions renders further development under the original permission unlawful (certain limited exceptions apply).We anticipate this will cause significant difficulties from both a planning and a real estate perspective. Examples of common scenarios where difficulties will arise include:

  1. Buying an unbuilt development plot with planning permission that is part of a larger development site - someone else (whether the seller or another developer) on another part of the wider development has already implemented, or (post acquisition) implements a “drop-in” permission (or material unlawful development). This would generally render further development under the original permission unlawful and the buyer would then technically own a site without a planning permission.
  2. Selling an unbuilt development plot to another developer on a site with planning permission. The purchaser then decides, for example, to increase the amount of housing or floorspace by obtaining and implementing a “drop-in” planning permission. This would generally make further development under the original permission by the seller on its retained land unlawful.

The Hillside Parks case has been widely recognised as significantly limiting the use of “drop in” planning applications, particularly for large developments. It has been widely considered to be an impractical position in practice. It will be necessary to find difficult solutions for such applications where possible.

See our case summary.Freeths has devised strategies for handling these types of situations. Please get in touch if you wish to discuss.


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.

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