Back to the Drawing Board: UK Government's Net Zero Carbon Budget ruled unlawful, again.



In recent judicial review proceedings, the High Court has ruled that the UK government's Carbon Budget Delivery Plan ("the Plan") has fallen foul of the Climate Change Act 2008 (CCA) for the second time. It is also the second time Friends of the Earth, ClientEarth and the Good Law Project (the Claimants) have successfully challenged the UK government's climate plan. 

Why is this important? 

The decision is a pivotal example of how climate change legislation can be utilised to hold the UK government to account on its carbon budget policies and proposals. This is particularly the case where proposals are based on the development of future technologies and funding. These proposals and policies affect the whole country, economy, and the way the country does business internationally. The decision is likely to give impetus to claimants to hold the government to account for the effectiveness of net zero policies in practice. 


Following a 2022 ruling, the UK government was found to be in breach of legislation designed to help reach the 2015 Paris Agreement goal of containing temperatures within 1.5C (2.7F) of pre-industrial levels. The government was therefore ordered to publish a new report setting out a fresh budget with details of time frames, how the policy would affect the economy and transparency for the public on the government's net zero strategy. The government duly published its Plan in March 2023. 


The Claimants argued that the Plan breached section 13 of the CCA. This provision requires the Secretary of State for Energy Security and Net Zero ("the Energy Secretary") to prepare policies and proposals which will meet the carbon budgets of the CCA. The CCA establishes a framework by which the UK hopes to reach net zero by 2050 and includes 5-year carbon budgets aimed at reducing the UK's greenhouse gas emissions.

The Claimants made the following arguments:

1. The Plan did not address the risks that many of the policies referred to would not deliver the cuts needed to meet the climate targets, and assumed that the proposals and policies would be delivered in full;

2. The Energy Secretary (at the time, Grant Shapps) lacked sufficient information on the level of risk to delivery of the strategies when they were approved; and 

3. The future technologies that the Plan relies on are stated to be high risk, calling into question the achievability of the Plan.

As to the first argument, Judge Sheldon found that "the [Energy Secretary] did make his decision on the assumption that each of the proposals and policies would be delivered in full" which meant "the [Energy Secretary]’s decision was taken on the basis of a mistaken understanding of the true factual position." As a result of this assumption "the [Energy Secretary] made an irrational decision" based on a reasoning which was not justified by the evidence put to him. 

As to the second argument, Judge Sheldon found that the Energy Secretary was provided with information and mitigation measures for the policies and proposals which formed the Plan. However, that information was incomplete, making it impossible to determine whether a target was realistic.

Crucially, under the CCA, deciding whether the policies and proposals will meet the target is a decision for the Energy Secretary alone and the lack of sufficient information made it impossible for him to make an assessment of whether a policy and/or proposal will meet a target or be delivered in full.

This is important because in the first case brought by the Claimants against the Energy Secretary, Judge Holgate had made explicit that the Plan needed to have:

“[s]ufficient information on delivery risks to make an informed judgment about whether carbon budgets can be met. This must include qualitative explanation of risks and planned mitigations, in addition to Red Amber Green ratings, building on existing work on monitoring delivery risks.”

In addition, section 13(3) of the CCA requires the policies and proposals, taken as a whole, to contribute to sustainable development. Judge Sheldon found that the Energy Secretary's assessment that the policies and proposals were "likely" to contribute to sustainable development fell short of the obligatory statutory requirement. 

Speaking after the judgment was handed down, the lawyer for Friends of the Earth, Katie de Kauwe, commented: “This is another embarrassing defeat for the government and its reckless and inadequate climate plans. We’ve all been badly let down by a government that’s failed, not once but twice, to deliver a climate plan that ensures both our legally binding national targets and our international commitment to cut emissions by more than two-thirds by 2030 are met."

Responding to the judgment, a spokesperson for the Department for Energy Security and Net Zero said: "The claims in this case were largely about process and the judgment contains no criticism of the detailed plans we have in place. We do not believe a court case about process represents the best way of driving progress towards our shared goal of reaching net zero." (Reuters)

What next? 

The Court will make an order setting out what the Energy Secretary needs to do and in what timeframe. It is likely that the current Energy Secretary, Clare Coutinho, will have 12 months to produce a revised plan. Any plan will need to ensure that the UK is on track to meet its legally binding carbon budgets as well as its pledge to cut emissions by more than two-thirds by 2030. 

This article has been co-written by Sanchita Agrawal (Solicitor) and Kerry Price (Trainee Solicitor).

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