Andrew Boswell, R (on the application of) v The Secretary of State for Transport

Environmental impact assessment of greenhouse-gas emissions requires an appropriate assessment of significant cumulative effects. The adequacy of that assessment is ordinarily a matter of fact and evaluation for the decision-maker, subject to supervisory judicial review.

Where greenhouse-gas emissions have global effects and the applicable carbon budgets are national and economy-wide, it may be rational to assess a road scheme in its affected road-network context and against national carbon budgets. The legislation does not require a separate assessment aggregating an arbitrarily selected group of local projects where that exercise has no logical or scientific basis and adds no useful information.

Dr Boswell challenged three grants of development consent for related A47 road improvement schemes near Norwich. He alleged that the Secretary of State had failed to assess lawfully the cumulative greenhouse-gas emissions of the schemes under The Infrastructure Planning (Environmental Impact Assessment) Regulations 2017.

The Planning Court dismissed the three judicial review claims: [2023] EWHC 1710 (Admin). With permission limited to one ground, Dr Boswell appealed. He contended that the Secretary of State had to assess the significance of the combined emissions of the three schemes against national carbon budgets, rather than assessing each scheme in its affected road-network context.

1. Appeal dismissed. Sir Launcelot Henderson, with whom Dingemans and Peter Jackson LJJ agreed, held that the Secretary of State had lawfully discharged the environmental impact assessment duties.

2. The court accepted that the environmental statements had to describe likely significant effects resulting from cumulation with other existing or approved projects. That obligation was met through the affected road-network modelling, the examination process, and the environmental information considered by the Secretary of State. Environmental impact assessment is a process, rather than an exercise confined to the environmental statement.

3. The existence and adequacy of cumulative effects assessment were matters of fact and evaluation for the decision-maker. The court’s role was supervisory. It would intervene for a legal error, irrationality, or a demonstrable flaw in reasoning, not because another evaluative approach might have been preferable.

4. Greenhouse-gas emissions differ from geographically bounded impacts such as noise or dust. Their effects are global. In the absence of a geographical or sectoral carbon target, there was no logical basis for selecting the three local schemes, rather than other emitting projects, for a separate aggregate comparison with national carbon budgets. Such an exercise would create a spurious appearance of precision.

5. The Secretary of State had addressed cumulative effects, considered the representations, and adequately explained why no separate wider assessment would be meaningful. Assessing each independent scheme in the wider context of its affected road network, and against national economy-wide carbon budgets, was rational and compatible with The Infrastructure Planning (Environmental Impact Assessment) Regulations 2017. No error of law or irrationality was shown.

• Court of Appeal (Civil Division): dismissed Dr Boswell’s appeal from the Planning Court. [2024] EWCA Civ 145
• High Court, King’s Bench Division, Planning Court: dismissed the three judicial review claims challenging development consent for the road schemes. [2023] EWHC 1710 (Admin)