Legal advice on planning policy

A growing number of Local authorities have introduced Net Zero Carbon new building policies in their Local Plans based on energy metrics. These policies are based on robust technical and cost evidence. However, at the end of 2023 a Written Ministerial Statement (WMS) challenged this approach and put into question whether local authorities could set higher environmental standards with different metrics than those used in Part L.

We have investigated this, had legal advice, and found that local authorities can still bring forward Net Zero Carbon new building policies based on energy metrics. You can download this formal open written advice in the link below.

Policy options for reducing operational carbon emissions

Delivering Net Zero is a technical and cost evidence base undertaken for 18 London boroughs in collaboration with Levitt Bernstein, Inkling, Introba and Currie & Brown. This looked at the effectiveness and likely outcomes from two policy options:

Policy Option 1 – using the Part L framework and Part L modelling

Policy Option 1 operates within the framework of Part L 2021, continuing the current practice of focusing on reducing regulated carbon emissions by a certain percentage. This option emphasises a single metric: the percentage reduction in carbon emissions compared to the baseline set by Part L 2021. It allows for carbon offsetting to play a significant role in achieving Net Zero status.

However, it does not address emissions from equipment and appliances (unregulated emissions) and relies on energy modelling that does not predict actual energy use. There is no feedback on whether buildings have been successful in achieving the carbon reduction. This option is seen as a continuation of existing practices but has limitations in its effectiveness and measurability in truly achieving Net Zero Carbon developments.

Policy Option 2 – using energy-based metrics and predictive energy modelling

Policy Option 2 proposes a more comprehensive approach by incorporating a suite of energy-based metrics. This option focuses on achieving absolute energy use targets, banning the use of gas boilers in new buildings, and utilising predictive energy modelling to ensure that buildings meet Net Zero Carbon standards in operation. It considers all energy uses within a building and seeks to balance energy consumption with on-site renewable energy generation.

Policy Option 2 is designed to be more transparent, effective, and easier to monitor, as it is based on measurable outcomes rather than theoretical reductions. Policy Option 2 has already been adopted by Cornwall Council, Bath & North East Somerset Council and Central Lincolnshire Council. It is being considered by many other local authorities across the country.

Legal advice on local planning policy

Etude commissioned Estelle Dehon KC, a public law barrister with expertise in planning law, to advise on the correct legal approach to such policies in light of the 2023 Written Ministerial Statement (WMS). We also asked for her advice on the general conformity of these policy options with the London Plan.

The advice is particularly useful given the latest Climate Change Committee (CCC) report to Parliament (July 2024) and in particular the fact that it highlighted concerns over the 2023 WMS, which it said would be “likely to cause further confusion and delays around adopting Local Net Zero policies, which is a setback“. The CCC also highlighted that the “spatial planning system continues to cause issues for delivering Net Zero“.

We have now received her written advice and she is happy for us to share it in the form of an ‘open written advice’ which you can download here:

Download the open written legal advice on the 2023 WMS

Key headlines from open written advice on WMS 2023

1. The 2023 WMS does not prevent local plan policies based on Policy Option 2 (energy-based metrics) from being brought forward by local planning authorities or being found sound in examination. 

2. The 2023 WMS is policy guidance to which regard must be had, but from which deviation can be justified in so long as there is clear evidence which provides the reasons for so doing, and which demonstrates the viability of policies based on Policy Option 2. A robust evidence base – a reasoned and robustly costed rationale – is necessary to enable examining inspectors to determine that policies based on Policy option 2 are consistent with national policy on climate change mitigation and the Climate Change Act 2008 Net Zero obligation, and that any deviation from the 2023 WMS is justified.

3. The advice includes a review of the RCA judgment. It highlights that “The Secretary of State rejected the contention that the 2023 WMS sets a “default instruction” to inspectors. Instead, the Secretary of State argued that “the policy is simply setting out guidance on what the Secretary of State considers to be reasonable”, i.e. “a reasoned and robustly costed rationale”. It also states that “The RCA judgment rejected the contention that the 2023 WMS emasculated or was incompatible with the powers in section 19 of the Planning and Compulsory Purchase Act 2004. It is certainly correct that the 2023 WMS does not constrain or delimit the extent of the duty in section 19(1A).”

We hope that you will find this open written advice useful. Please contact Etude if you would like more input on developing local policy to reduce carbon emissions.