Douglas Adams’ Hitchhiker’s Guide to the Universe poked fun at many of the absurdities of life on our planet. Triggered by another absurdity of our English planning system, a reminder of which is within R (WildFish) v Buckinghamshire Council (13 March 2026) (Court of Appeal, 13 March 2026), I watched again the opening sequence from the movie (Dolphins: So long, and thanks for all the fish / So sad that it should come to this / We tried to warn you all, but, oh, dear / You may not share our intellect / Which might explain your disrespect / For all the natural wonders that grow around you / So long, so long, and thanks for all the fish! The world’s about to be destroyed / There’s no point getting all annoyed / Lie back and let the planet dissolve around you / Despite those nets of tuna fleets / We thought that most of you were sweet …).
The absurdity I’m thinking about today isn’t about the way in which public consultation processes are sometimes carried out, which Adams did cover (tldr: cellar; no lights; no stairs; “beware of the leopard” sign), but about the lack of fit-for-purpose legislation to amend planning permissions. Yes we all know about Hillside case by now (see my 2 November 2022 blog post if you have literally been on another planet). Yes we all know about the constraints on section 73 following Fiske (space traveller, this 11 December 2024 blog post may help). And yes we know that we are still waiting for section 73B to be switched on which may help with the latter (subject to a new “not substantially different” test) but not with the former.
But the system for amending permissions is even more basically kaput than that, as the Wildfish case illustrates.
The issue isn’t one which was central to the litigation but I’ll briefly explain the case first. It was a judicial review by an environmental campaign group of a reserved matters approval for a housing development. Outline planning permission had been granted on 24 March 2022 for a development of up to 170 dwellings. Condition 13 on the permission provided as follows:
“The details to be submitted for approval in writing by the Local Planning Authority in accordance with Condition (1) above shall include a foul water drainage scheme for the site. The scheme shall include a waste water treatment capacity assessment to identify the need for any infrastructure upgrades and a programme for carrying out the works to inform site delivery.
No part of the development shall be occupied until confirmation has been provided to the local planning authority that the scheme and programming of any wastewater upgrades required to accommodate the additional flows from the development have been agreed with Anglian Water; and all wastewater upgrades required to accommodate the additional flows have been completed. The development shall be carried out in accordance with the approved details.”
Condition 2 required reserved matters applications to be submitted within 18 months of the permission. The reserved matters application was submitted in time on 25 May 2023. Whilst it was being determined, the applicant had further discussions with Anglian Water and a section 73 permission was granted on 10 December 2024 for “Variation of Condition 13 of 16/00151/AOP on Land off Walnut Drive and Foscote Road to allow details to be submitted prior to occupation.” The section 73 permission incorporated a version of condition 13 without its original first paragraph, i.e. which no longer required that the details to be submitted for reserved matters approval should include the “waste water treatment capacity assessment to identify the need for any infrastructure upgrades and a programme for carrying out the works to inform site delivery”.
The applicant then revised the reserved matter application to refer to section 73 permission (so as to explain why It wasn’t accompanied by the detail which condition 13 had previously required) and it was granted on 4 March 2025.
The environmental group pursued two grounds of challenge to the reserved matters approval at the Court of Appeal hearing:
“Ground one is the contention that as a result of what occurred in this case there was a substantial alteration to the reserved matters application which meant that the first respondent had no power to approve it. The appellant’s argument is that since condition 13 requires details “to be submitted for approval in writing by the local planning authority in accordance with condition (1) …” the requirements of condition 13, and all of them, are temporally linked to condition 1. The submissions which are required by condition 1 are necessarily linked in the terms of the condition to the time limit in condition 2.”
“Turning to ground two, the appellant contends that it was unlawful, in effect, to switch the reserved matters application from one parent permission, the outline permission, to another, the section 73 permission, in particular when the timescale for submitting reserved matters under the section 73 permission had clearly expired. It was unlawful for the first respondent to consider and determine the reserved matters application “with reference to” the section 73 permission. The section 73 permission was, in accordance with the authorities, an entirely new and separate permission from the outline permission. Had the second respondent wished to discharge reserved matters under the authority of the section 73 permission it would have needed to have applied to do so but in fact the time to do so had passed.”
The Court of Appeal rejected both grounds. On the first ground, details of a foul drainage scheme fell outside the definition of “reserved matters” and so the fact that the details required by condition 13 of the outline planning permission had not been included did not mean that a valid reserved matters application had not been submitted by the 18 months deadline. On the second ground, the amendment of the application to refer to the section 73 permission did not cause the application to be one that had been submitted under the section 73 permission. Dove LJ states: “Firstly, in my view reading all the documents together, the proper conclusion is the one which I have already set out, namely that the reserved matters application, specified in the application to be for the outline planning permission and described thereafter as such subject only to the observation of a “variation” which was at best merely recording the fact of the section 73 permission, the reasonable reader would have concluded the reserved matters were approved under the outline permission.”
However, the important reminder is what immediately follows:
“It is important to re-emphasise what was observed by Sullivan J in Pye, namely that whilst in statutory language and also common usage a section 73 application is described as a “variation” or “amendment” the truth is that it creates an entirely separate permission. That language is capable of being seriously misleading. The mere reference in the amendment to the description of the existence of an entirely separate planning permission was not in my judgment capable of either transferring the reserved matters application to that entirely separate permission or, alternatively, leading to the inference that permission was being granted under both the outline permission and the section 73 permission.”
What is this reminding us? Well, in basic terms, if you secure reserved matters approval pursuant to an outline planning permission but there is a problem with complying with one of the conditions on the outline planning permission and so you apply to “amend” it under section 73, that “amendment” isn’t engaged, and doesn’t help you, in relation to your build-out of the reserved matters approval. Your reserved matters approval was granted pursuant to the initial outline planning permission. The section 73 application, once approved, results in a separate outline planning permission and the “amendment” would only help you in relation to reserved matters approvals secured pursuant to that section 73 permission (and the deadline may well have expired for submitting reserved matters applications, given that of course – another frustration- section 73 applications can’t be used to secure extensions of time limits for submission of reserved matters or for implementation).
So it is really important to follow the family tree in relation to any planning permission where section 73 permissions have been secured. Under what planning permission were the reserved matters approved that are now being relied upon? If reliance is being placed on any amended form of condition to that contained within the original outline planning permission, is the scheme actually being built out pursuant to that planning permission?
This is a wrinkle which arises with use of section 73, as section 73 application of course results in a fresh permission. The same wrinkle will arise with section 73B. It does not arise with non-material amendments approved pursuant to section 96A, as with section 96A, of course, there is no new permission; the existing permission is varied.
As always, there are potential work-arounds. Often indeed I’m sure the issue goes unnoticed, because after all, where is the “planning harm”? But it’s another one to watch out for. NB thank you to Killian Garvey, whose LinkedIn post on the issue got me a-thinking.
Final Douglas Adams quote, for now at least:
“Narrator: There is a theory which states that if ever anyone discovers exactly what the Universe is for and why it is here, it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another theory mentioned, which states that this has already happened.”
Simon Ricketts., 19 April 2026
Personal views, et cetera


