Supreme Court clarifies cumulative approach to FOIA public interest exemptions

The UK Supreme Court's July 2025 judgement in Department for Business and Trade v The Information Commissioner has resolved a fundamental question about how public interest exemptions operate under the Freedom of Information Act 2000 (FOIA). The case establishes that when multiple exemptions are engaged, public interest factors should be assessed cumulatively rather than independently.

The dispute originated from journalist Brendan Montague's November 2017 request for information about trade working groups developing post-Brexit arrangements. The Department for Business and Trade partially disclosed the requested material but withheld substantial portions under sections 27 and 35 of FOIA—exemptions covering international relations and government policy formulation respectively.

Following the Information Commissioner's initial support for the Department's position, Montague pursued judicial review proceedings that highlighted a critical interpretative divide. The central question concerned whether public interest factors supporting non-disclosure could be aggregated across multiple exemptions or whether each exemption required separate assessment.

The First-tier Tribunal favoured the cumulative approach, permitting the aggregation of public interest factors from different exemptions when determining whether the overall public interest favoured withholding information. Conversely, the Upper Tribunal adopted an independent assessment methodology, concluding that the public interest in maintaining the exemptions did not outweigh disclosure interests for the withheld material.

The Court of Appeal reversed this position, endorsing the Department's cumulative approach as providing more coherent public interest analysis. This appellate decision prompted the Supreme Court appeal, which focused specifically on interpreting section 2(2)(b) of FOIA.

The Supreme Court unanimously endorsed the cumulative approach, emphasising that comprehensive consideration of all relevant public interest aspects is essential when determining whether exemption maintenance outweighs disclosure interests. The Court reasoned that cumulative assessment enables decision-makers to evaluate the collective weight of non-disclosure factors, producing more accurate public interest determinations.

Crucially, the judgement noted that FOIA's provisions do not restrict public interest test application to individual exemptions. Instead, the statutory framework encourages comprehensive evaluation of public interest implications across multiple exemptions. This interpretation ensures that cases involving multiple exemptions receive more rigorous public interest evaluation.

However, the decision was not without dissent. Lord Richards and Sir Declan Morgan raised concerns about legal clarity and the potential for cumulative approaches to blur individual exemption boundaries. Their dissent highlights ongoing tensions between comprehensive public interest assessment and maintaining distinct exemption categories.

The judgement represents a significant development in FOIA jurisprudence, establishing clear precedent for future cases involving multiple exemptions. The ruling reinforces governmental transparency principles whilst acknowledging necessary protections for sensitive information relating to international relations and policy development.

The practical implications extend beyond this specific case. Public authorities can now more confidently rely on cumulative public interest arguments when multiple exemptions apply, whilst information requesters and their advisers must consider how various exemption categories might interact to strengthen non-disclosure positions.

This precedent fundamentally alters the FOIA landscape by providing clearer guidance on public interest balancing exercises. The Supreme Court has effectively endorsed a more holistic approach to information disclosure decisions, recognising that the public interest rarely operates in isolation but rather through complex interactions between competing considerations.