1028: Hillside Parks & DCO projects, and a challenge to the Energy National Policy Statements

Today’s entry looks at a recent case in relation to overlapping planning permissions and a challenge to the Energy National Policy Statement (EN-1 and EN-3).

Caught in a Hillside

We previously set out what the Hillside judgment means for DCO projects. For context, the starting position is that you can seek overlapping and, indeed, inconsistent planning permissions over the same site. However, the implementation of such permissions is subject to the principle established in Pilkington v Secretary of State for the Environment [1973] 1 WLR 1527 and endorsed by the Supreme Court in Hillside Parks.

The principle is that, where development has taken place under one permission, whether another planning permission may lawfully be implemented depends upon whether it remains physically possible to carry out the development authorised by the second permission in light of what has already been done under the first permission. That principle is subject to any ‘clear express provision’ to the contrary. In our previous post noted four scenarios that could engage the principle. I won’t repeat what we set out there, but go back and read that for examples of the interface between DCOs and planning permissions. What has happened since? Well, there are two key updates.

The first update is the case of Dennis v London Borough of Southwark [2024] EWHC 57 (Admin). In that case, Southwark Council granted permission for a ‘slot in’ application on the basis that separate development zones meant the previous permission was severable. It then treated the addition of ‘severable’ as a non-material amendment to a masterplan scheme. The High Court held this was unlawful. While the case was primarily about whether the planning permission could be severable, there are some interesting confirmatory comments in the case relating to Hillside Parks.

In particular, the High Court confirms that ‘when granting permission for such a scheme, the authority cannot be taken, “absent some clear contrary indication,” to have authorised the developer to combine building part only of the proposed development with building something different from and inconsistent with the approved scheme on another part of the site.’

Mr Justice Holgate is clear that the ‘test of physical impossibility applies to the whole of the site covered by the permission in question’ and goes on to note explicitly:

‘An issue could arise as to whether any development carried on thereafter pursuant to a different permission makes it physically impossible to carry out development previously approved as reserved matters under the outline permission. If the answer is yes, then that approval of reserved matters could no longer be relied upon unless, on a true interpretation, the grant of outline planning permission was severable in some relevant way.’

This case makes it clear that promoters must be very careful about the risk of a DCO overlapping with an existing planning permission. For example, where the Order limits look at land that is subject to a planning permission, there may be a risk that if works are carried out under the DCO, which gives rise to an inconsistency with a previous planning permission, then that previous planning permission, in the words of Mr Justice Holgate, ‘could no longer be relied upon.’

The second update relates to new precedents in the DCO context. As we noted in our previous post, DCOs and TWAOs are grappling with this issue already, and recent DCOs have continued that trend. Here are a few examples since Hillside Parks:

• Article 8(2) of The Drax Power Station Bioenergy with Carbon Capture and Storage Extension Order 2024 which states that any previous permission granted under the TCPA is ‘excluded and does not apply, but only insofar as such approval, grant, permission, authorisation or agreement relates to the Order limits and is inconsistent with the authorised development and anything approved under the requirements.’
• Article 8 of the Slough Multifuel Extension Order 2023 sets out that ‘anything done by the undertaker in accordance with this Order does not constitute a breach of any planning permission issued pursuant to the 1990 Act.’

Those examples make sure the DCO in question can be carried out even if it would be incompatible with an earlier planning permission, but what about future slot-in planning permissions? There are also some draft DCOs that address this matter (see, for example, article 56 here, a provision generally welcomed by local authorities).

ChallEN-1ge

Meanwhile, the Good Law Project has launched a challenge to the designation of EN-1 and EN-3; their pre-action protocol letter can be found here. What is the basis of this challenge? The Good Law folks note that the NPS must give reasons for the policy and must, in particular, include an explanation of how that policy has taken into account mitigation and adaptation to climate change.

They say the government has failed because there is no explanation for omitting onshore wind and ‘not addressing the reasons for its continued omission.’ In continuing to exclude onshore wind, the government is also – so says the Good Law Project – ignoring the recommendations of the National Infrastructure Commission. Even though onshore wind is not currently within the scope of the Planning Act 2008, the government should have nonetheless considered it.

Well, my money is the challenge failing even though the exclusion of onshore wind is something this blog has railed against.