Section 35B of the Planning Act 2008 – the “opt-out” power

Summary

Section 35B of the Planning Act 2008 (the Planning Act) has come into force and allows for applications to be made to the Secretary of State to direct development out of the NSIP/DCO regime, to instead be considered and determined through an alternative consenting regime – the “opt-out” power. Previously developers were forced to get a DCO if their project met the NSIP thresholds (so many scoped their projects to avoid this) but now developers can ask to opt-out if that is better for their projects. 

Analysis

Whilst much of the commentary and focus of the changes to the NSIP/DCO regime introduced by the Planning and Infrastructure Act 2025 has centred on the significant changes to the pre-application and acceptance stages (as discussed in our article here), a less-heralded, but similarly significant change has also recently come into force – the so called “opt-out” power under Section 35B of the Planning Act. 

Previously, Section 35 of the Planning Act was “one-way” facing, allowing for an application to be made to the Secretary of State (SoS) to direct that a particular project should be treated as development for which development consent is required. An “opt-in” provision, in-effect, and which has been relied upon in a number of instances and across a broad range of sectors over the years. We have advised many clients on this process and successfully obtained opt-in directions across a range of projects, from the Aquind Interconnector to Cornish Lithium’s Trelavour Downs.

Section 35B of the Act now provides for the inverse – an “opt-out” power, allowing for development that would ordinarily require development consent under the Planning Act to instead be directed by the SoS to be considered through an “alternative consenting regime”.

To pick-up on some of the procedural logistics attaching to the Section 35B power:

• It shares the same territorial application as for the original Section 35 power, namely, that such a direction may only be given where the development will (when completed) be wholly in England (or waters adjacent to England up to the seaward limits of the territorial sea), or in the case of development in the field of energy, in a Renewable Energy Zone (except any part of the Zone where the Scottish Ministers have functions).
• As part of an application for an “opt-out” direction, the “requestor” (or qualifying person, to use the language of the provision itself) must explain why they consider it is appropriate for the proposed alternative consenting regime to apply, rather than the NSIP regime, in relation to the development and include evidence showing that the alternative consenting authority is aware of the intention to request such a direction. 
• “Alternative consenting regime” is defined in Section 35B as “a regime set out in legislation other than [the Planning] Act under which, if development consent were not required for the development, a specified person would have power to authorise the development”, with “alternative consenting authority” defined by reference to the “specified person” in that same definition. 
• Under the Infrastructure Planning (Timetable for Deciding Request for Direction) Regulations 2026, the SoS, on receiving a qualifying request, must make a decision on the request within 35 calendar days, with such period resetting where the SoS requests additional information to assist with the determination. 

Guidance on the use of the opt-out power

The Government published guidance alongside this new provision coming into force: Planning Act 2008: Guidance on powers to direct a project into or out of the NSIP regime (the Guidance), which helpfully elaborates on the process and gives an indication as to the Government’s anticipated application of this new power. 

Specific to the need to evidence the awareness of the alternative consenting authority as to the intention to submit a request, the Guidance goes further by noting that, where possible, the authority’s written views on the proposed use of the alternative consenting regime should be included with the request. In the absence of such views being included, the Guidance expects that at a minimum confirmation of prior engagement on the matter should be included, together with an explanation as to why the written views are not available. 

Early engagement with the alternative consenting authority is therefore strongly encouraged through the Guidance and it reads implicitly to me that in the absence of consensus with that authority, the Section 35B application may be up against it (at least in the early stages of this provision’s lifespan, where the SoS will no doubt err on the side of caution in making such direction). That said, that may not be a problematic limitation in practice in any case, as presumably one of the motivating factors for making such a request would be where prospective developers consider there is a supportive local planning authority (LPA) for the principle of the application at the very least. 

In relation to the decision itself, the Guidance also elaborates on how the SoS may determine whether it is appropriate for the alternative consenting regime to apply in relation to the development. Relevant factors are set out in detail, but broadly focus on whether that “regime is proportionate to the nature, scale, complexity and impacts of the project.” Although not specified in quite these terms, the inference would seem to be that the more significant the scheme is in terms of scale, complexity or impact – the less likely it is that the SoS would consider an alternative consenting regime to be appropriate. 

Section 9 of the Guidance goes on to consider some of the potential alternative regimes that could apply, with certain differences to the NSIP regime highlighted, but without drawing specific conclusion as to the appropriateness of that regime by consequence. There are no surprises to those regimes listed by way of example (Town and Country Planning Act 1990 (TCPA), Transport and Works Act, Highways Act etc).

The examples given of other potentially relevant matters – “whether the element that would otherwise require development consent forms part of, supports, or is closely connected to a wider project, and whether there would be a benefit in the relevant components being considered together through the same consenting route” and “whether the proposed alternative regime, alongside any other permits, licences, or consents required for the development, would provide a sufficiently complete, coherent, and deliverable consenting route for all relevant elements of the project…” – suggests that to the extent there was a wider development in process, severing this particular component through a Section 35B direction and removing it from the DCO regime may be unlikely to succeed. Whilst not prescriptive, the example relevant matters listed in the Guidance and accompanying tone would suggest to me that the scope of the power is primarily anticipated to be applied to discrete and geographically constrained developments (potentially single LPA), that do not give rise to any novel or complex consenting considerations. 

Energy projects

One slightly odd nuance is that for applications for Section 35B directions relating to “energy infrastructure” (those covered under Part 3 of the Planning Act), there are further additional factors set out in the Guidance which it is stated the SoS will consider when responding to such a request. In particular, it is stated that the SoS will “have regard to the government’s energy security and clean energy objectives, the Clean Power 2030 Action Plan published in December 2024, and the government’s target to cut Green House Gas emissions to Net Zero by 2050 including Carbon Budgets and Nationally Determined Contribution". 

As such, applications in this field are expected to clearly demonstrate the proposed development’s contribution to Clean Power 2030 and Net Zero targets, with the SoS in turn considering:

1. the proposed development’s generating capacity, including how close it is to the existing NSIP threshold for that technology at the time when the application for the section 35B direction is made; and
2. whether the proposed development includes a fossil fuels component; and
3. may also have regard to whether the direction would result in outcomes that do not align with wider government energy and clean power objectives. 

I think this is probably geared towards capturing energy schemes that may be perceived as not contributing to Clean Power 2030 or the trajectory towards Net Zero, with a presumed concern that surrendering determination of such schemes to an alternative consenting regime may allow for decisions to be taken which the Department for Energy Security and Net Zero (DESNZ) would regard as contrary to those policy/legislative objectives. 

Indeed, the Guidance is clear that “unabated fossil fuel projects”, such as non-low carbon electricity generation, pipelines and fuel storage will not be considered appropriate for a Section 35B direction except in exceptional circumstances. This is stated to be justified on the basis that “The NSIP regime provides a clear and comprehensive framework for considering the wider impacts of such projects under the national policy statement (‘NPS’), including requirements to carry out a whole life greenhouse gas assessment of the proposed development, and to provide an explanation of the steps that have been taken to drive down the climate change impacts at each stage of the life cycle of the development.”

For low-carbon electricity generation infrastructure projects on the other-hand (which are aligned with Clean Power 2030/Net Zero), I suspect the practical limitation on the application of “opt-out” directions may be more focussed on the scheme’s scale and overall generation capacity, considering the reference in the Guidance to the need to provide such details and by comparison to the existing NSIP threshold for that technology. 

I would assume the implication is that the greater the difference from the NSIP threshold to the scheme’s proposed generation capacity, the less likely it is the SoS would deem the alternative consenting regime to be appropriate. In the context of thresholds being set to determine schemes which have “national significance”, one can see the logic of that rationale; however, if the alternative consenting authority is content with the proposal to consider the application and there is the expectation of a speedy positive determination, and so more immediate contribution to such clean energy targets/outcomes, then it’s not obvious to me why the SoS would determine negatively (even where there is a bigger gap). Hopefully the SoS is open-minded on this point, and applies some weight to the views of the proposed developer who, of course, is assuming the risk and is most incentivised to secure a robust consent timeously. If they’re convinced by the merits of the alternative consenting regime, and there is (at least) no push back from that regime’s authority to such proposal, then it would be hoped that this would be persuasive to the SoS. 

Regardless, it strikes me that the Section 35B direction option may be particularly attractive to energy developers, and particularly potentially in the onshore wind and solar sectors, where there may be some marginal calls around pursuing TCPA or DCO scale schemes (given the significant cost differences between promoting applications under those respective regimes), with some capacity “left on the table” so to speak where the former is pursued. There are of course inherent drawbacks to TCPA determination by comparison (eg will be determined under local, rather than national, policy and so no Critical National Priority status and no compulsory acquisition powers available) and so any such decision would need to be considered having regard to a variety of factors and their relative pros/cons, but the ability to have genuine optionality around such a decision and project scope (rather than automatic thresholds) is helpful.

It will be interesting to see how the market evolves in response, and whether pursuing a Section 35B direction is considered a worthwhile endeavour in view of the potential to allow for TCPA determination of a scheme in excess of 100MW and potentially further maximising the extent of any grid connection obtained. 

I would be very happy to discuss strategy and approach with prospective developers who would like to explore this further.