The Gladman Judgment: What It Means for the Sequential Test

The Sequential Test is one of the most important — and most contested — elements of the flood risk planning framework in England. It requires local planning authorities to direct development away from areas at highest risk of flooding, and it is the first hurdle that any development proposal in Flood Zone 2 or 3 must clear.

The application of the Sequential Test has been the subject of numerous planning appeals and legal challenges. Among the most significant is the judgment in Gladman Developments Ltd v Secretary of State for Housing, Communities and Local Government [2021] EWCA Civ 104, which clarified several key aspects of how the Sequential Test should be applied.

This article examines the Gladman judgment, explains what it decided, and sets out the practical implications for developers, planning consultants, and local planning authorities.

Background

The Sequential Test

The Sequential Test is established by the National Planning Policy Framework. The NPPF states that development should not be allocated or permitted if there are reasonably available sites appropriate for the proposed development in areas with a lower risk of flooding.

The Planning Practice Guidance provides further detail on how the Sequential Test should be applied, including:

• The area of search should be agreed with the LPA
• The area of search is usually the LPA’s administrative area
• Reasonably available sites should be suitable, available, and achievable
• The Sequential Test can be narrowed for certain types of development that have specific locational requirements

The Gladman Case

Gladman Developments Ltd applied for outline planning permission for a residential development on a site that was partly in Flood Zone 2 and partly in Flood Zone 3. The application was refused by the local planning authority and subsequently dismissed at appeal.

One of the central issues was whether the Sequential Test had been properly applied. Gladman challenged the Inspector’s decision in the High Court, and the case eventually reached the Court of Appeal.

The Key Issues

The Gladman judgment addressed several important questions about the Sequential Test:

1. What Is the Correct Comparator?

One of the fundamental questions in any Sequential Test is: what are you comparing? Is the correct comparator the proposed development (the specific scheme, with its specific number of homes, layout, and design), or is it the proposed type of development (residential, in this case)?

The Court’s answer: The Sequential Test compares the type of development, not the specific scheme. The question is whether there are reasonably available sites at lower flood risk that could accommodate residential development of the type proposed, not whether there are sites that could accommodate the exact scheme proposed.

This is an important distinction. Under the previous interpretation favoured by some developers, a site-specific Sequential Test could be passed by arguing that no other site could accommodate the exact number and type of homes proposed. The Gladman judgment closed this argument by confirming that the test is about the type of development, not the specific proposal.

2. Does the Site Have to Accommodate All of the Development?

A related question is whether a sequential alternative site must be able to accommodate the entire proposed development, or whether it need only accommodate a substantial part of it.

The Court’s approach: The Court confirmed that the Sequential Test requires consideration of whether the proposed development (or development meeting the same need) could be accommodated on a site at lower flood risk. This does not require the alternative site to be identical in size or capacity to the proposed site. A smaller site that could meet a significant proportion of the identified need could be a valid sequential alternative.

However, the Court also recognised that there are practical limits. An alternative site that could only accommodate a handful of homes would not be a reasonable alternative to a major housing scheme. The LPA must exercise reasonable judgment in determining what constitutes a genuine alternative.

3. Who Bears the Burden of Proof?

The Sequential Test is applied by the LPA, but who bears the burden of demonstrating that it is passed?

The Court’s position: The burden is on the applicant to demonstrate that the Sequential Test is passed. The PPG states that the applicant should undertake the Sequential Test, supported by evidence. The LPA then assesses whether the test has been applied correctly and whether the evidence is convincing.

In practice, this means the developer must proactively identify potential alternative sites, assess their availability and suitability, and demonstrate why the proposed site is sequentially preferable. Simply asserting that no alternatives exist is not sufficient — the developer must show the work.

4. What Is the Appropriate Area of Search?

The area of search defines the geographic scope within which alternative sites are considered. The PPG states that the area of search should be agreed with the LPA, and that for most development types, it will be the LPA’s administrative area.

The Court’s guidance: The Court confirmed that the area of search is a matter of planning judgment for the LPA, guided by the PPG. The default area of search is the LPA’s administrative area, but it can be widened or narrowed depending on the circumstances:

• Wider area of search: Where the development meets a need that extends beyond the LPA’s boundary (for example, strategic housing need in a wider housing market area), a wider area of search may be appropriate.
• Narrower area of search: Where the development has specific locational requirements (for example, proximity to a specific town centre, employment area, or transport node), a narrower area of search may be justified.

The Court emphasised that narrowing the area of search must be justified by genuine planning considerations, not simply by the applicant’s commercial preferences.

5. How Rigorously Should Alternatives Be Assessed?

The level of detail required in the Sequential Test assessment has been a source of uncertainty. Some developers have argued for a light-touch approach; some LPAs have demanded exhaustive evidence.

The Court’s approach: The Court confirmed that the Sequential Test requires a genuine and meaningful assessment of alternative sites, but it does not require the applicant to demonstrate that every possible alternative has been exhaustively investigated. The test is one of “reasonably available” sites, which implies a practical and proportionate approach.

However, the Court also made clear that a cursory or superficial assessment will not suffice. The applicant must engage genuinely with the question of whether alternative sites exist and provide sufficient evidence to allow the LPA to make an informed judgment.

Practical Implications

For Developers

The Gladman judgment has several practical implications for developers proposing residential development in flood-risk areas:

Prepare a thorough Sequential Test assessment. The days of a brief letter asserting that no alternatives exist are over. The assessment should identify all potentially available sites within the agreed area of search, assess their flood risk, and explain why they are not suitable, available, or achievable alternatives.

Agree the area of search with the LPA early. The area of search is a matter of planning judgment, and disagreements about the area of search are a common cause of Sequential Test failures. Engage with the LPA at the pre-application stage to agree the area of search and the methodology.

Do not over-specify the development. The Sequential Test compares development types, not specific schemes. If you define your development too narrowly (e.g., “a scheme of exactly 150 homes with 30% affordable housing, a LEAP, and a community hall”), you risk being challenged for artificially narrowing the comparison. Instead, describe the development in terms of the type and approximate scale of housing proposed.

Consider the LPA’s housing land supply. If the LPA cannot demonstrate a five-year housing land supply, there is greater pressure on the LPA to grant permission for housing, but this does not override the Sequential Test. The Gladman judgment confirms that the Sequential Test must be applied even where there is a housing land supply deficit.

Keep records. Document the Sequential Test process — the area of search, the sites considered, the reasons for rejecting alternatives. This evidence may be needed at appeal.

For Local Planning Authorities

Apply the Sequential Test consistently. The Gladman judgment provides a clear framework for applying the Sequential Test. LPAs should apply this framework consistently to all applications in flood zones.

Define the area of search proactively. Rather than waiting for the applicant to propose an area of search, LPAs should develop and publish guidance on how they will define the area of search for different types of development. This provides certainty for applicants and reduces the scope for disputes.

Maintain up-to-date site information. The Sequential Test requires information about available sites. LPAs should maintain an up-to-date Strategic Housing Land Availability Assessment (SHLAA) or Housing and Economic Land Availability Assessment (HELAA) that includes information about flood risk.

Do not rubber-stamp. The Gladman judgment confirms that the LPA has a substantive role in assessing the Sequential Test. It is not sufficient to simply accept the applicant’s assessment at face value. The LPA should scrutinise the evidence, check the flood risk of alternative sites, and form its own judgment on whether the test is passed.

For Planning Consultants

Be honest about the Sequential Test. If there are genuine alternatives at lower flood risk, the Sequential Test will not pass, no matter how well the assessment is presented. It is better to advise the client at the outset that the Sequential Test may be a barrier, rather than allowing them to invest in a scheme that is likely to be refused.

Frame the test correctly. The comparison is between types of development, not specific schemes. Present the Sequential Test in these terms, and avoid the temptation to define the proposed development so narrowly that no alternative could possibly match it.

Address the LPA’s concerns. Engage with the LPA early and address any concerns they raise about the Sequential Test methodology. A collaborative approach is more likely to succeed than an adversarial one.

Subsequent Case Law

The Gladman judgment has been considered and applied in numerous subsequent appeal decisions. Some key themes from post-Gladman decisions:

Area of Search

Several inspectors have emphasised the importance of agreeing the area of search with the LPA before submitting the application. Where the applicant has used a narrower area of search than the LPA considers appropriate, inspectors have generally sided with the LPA.

Availability of Alternatives

Inspectors have adopted a practical approach to the availability of alternative sites. A site that is theoretically available but has no realistic prospect of being developed (for example, because it has insuperable planning constraints or is subject to a ransom strip) is generally not treated as a genuine alternative.

The Role of the SFRA

Several decisions have emphasised the importance of the Strategic Flood Risk Assessment in the Sequential Test process. Where the SFRA identifies sites at lower flood risk that could accommodate the proposed development, the applicant will need to provide a compelling explanation for why those sites are not genuine alternatives.

Sequential Test for Windfall Sites

Post-Gladman decisions have confirmed that the Sequential Test applies to windfall sites (those not allocated in the Local Plan) as well as to allocated sites. For windfall sites, the developer must demonstrate that no reasonably available sites at lower flood risk exist within the area of search.

The Wider Policy Context

The Gladman judgment sits within a broader policy context that is increasingly emphasising the importance of directing development away from flood-risk areas:

NPPF Revisions

The December 2023 revision of the NPPF reinforced the Sequential Test, clarifying that it applies to all development in flood-risk areas and that the area of search should be defined with reference to the LPA’s area unless there are compelling reasons to define it differently.

Climate Change

As climate change increases flood risk, more land will fall within flood zones, and the pressure on the Sequential Test will intensify. The Environment Agency’s updated climate change allowances (most recently revised in 2022) mean that design flood levels are higher, and more development will be affected.

Housing Need

The government’s target of delivering 1.5 million new homes in England over the current parliament creates significant pressure to find development land. In areas where much of the available land is in flood zones, there is an inherent tension between housing delivery and flood risk management. The Sequential Test is the mechanism through which this tension is resolved, and the Gladman judgment provides the legal framework for its application.

Conclusion

The Gladman judgment is a landmark decision that has brought clarity to the application of the Sequential Test. Its key principles — that the test compares development types, not specific schemes; that the burden is on the applicant; that the area of search is a matter of planning judgment; and that the assessment must be genuine and meaningful — provide a robust framework for all parties involved in the planning process.

For developers, the message is clear: take the Sequential Test seriously, engage with the LPA early, and provide thorough evidence. For LPAs, the message is equally clear: apply the test consistently, define the area of search proactively, and scrutinise the evidence.

At Aegaea, we prepare Sequential Test assessments and Flood Risk Assessments for residential and commercial developments across England. Our Chartered engineers understand the legal and policy framework established by the Gladman judgment and subsequent case law, and we provide the evidence needed to pass the Sequential Test or, where appropriate, to advise that an alternative approach is needed.

If you need help with a Sequential Test assessment, contact our team for a no-obligation discussion.