Development, Flood Risk and Planning Judgment: What Gladman and Recent NPPF/PPG Amendments Mean in Practice

Flood risk remains one of the main barriers to development in the UK. In England, around 6.3 million homes and businesses are already at risk of flooding, with climate change allowances now baked in to flood assessments.

The flood Sequential Test continues to play a central and often disputed role in determining planning applications. Recent proposed amendments to the NPPF, alongside updated guidance and the judicial approaches, have clarified how the Sequential Test should be applied and how its absence is weighed in the planning balance.

This blog considers what these changes mean in practice and whether they point towards a more pragmatic approach to flood risk.

What is the Sequential Test?

The Sequential Test is intended to steer development away from higher flood risk zones; development should not be located in areas at risk of flooding where alternative sites appropriate for the development are reasonably available in areas with a lower risk of flooding.

Recent case law (discussed below) has confirmed this position, reaffirming that the absence of a Sequential Test must be weighed alongside site-specific flood risk evidence, mitigation measures and the wider benefits of a proposal, rather than treated as an automatic reason for refusal.

Policy Shifts

The Planning Practice Guidance on Flood Risk and Coastal Change (PPG) was updated in September 2025 to clarify that:

1. Surface water, drainage, rainfall and groundwater flooding sources must be considered as well as river and tidal flooding (Paragraph 23).
2. The Sequential Test may not be required where developers can demonstrate that the ‘proposed layout, design, and mitigation measures would ensure that occupiers and users would remain safe from current and future surface water flood risk for the lifetime of the development…without increasing flood risk elsewhere’. (Paragraph 27)
3. The appropriate area for the Sequential Test will depend on local circumstances, including relevant catchment area, the type of development proposed and its needs. Paragraph 27a also clarified that for large areas in Flood Zones 2 and 3 where development is needed to sustain the existing community, sites outside those areas may be unlikely to provide reasonable alternatives.
4. A ‘reasonably available’ site is one where the location is suitable for the type of development proposed, can meet the same development needs and has a reasonable prospect of being developed within a comparable time frame.

The Government’s December 2025 draft NPPF suggested changes include:

1. Clearer and more explicit requirements for site-specific flood risk assessments, including for all developments in Flood Zones 2, 3a, and 3b, together with defined triggers for when an assessment is required in Flood Zone 1.
2. Reinforcement that flood risk from all sources, including surface water and future flood risk must be taken into account when applying the Sequential Test.
3. Clarification on the geographical scope of the Sequential Test, confirming that the area which it is applies should ‘not be greater than the anticipated catchment of the development in terms of its likely occupiers or users’.
4. Confirmation that Sequential Test does not need to be reapplied for allocated sites, where one was undertaken at the plan-making stage, provided there has not been a significant increase in the risk of flooding to the site subsequently, or the nature of the development itself has not changed.
5. Greater clarity on the circumstances in which the Sequential Test does not apply, including where a site-specific flood risk assessment demonstrates that built development (including access and egress) would be located wholly outside areas at flood risk, now and in the future.
6. A more structured approach to the Exception Test, including when it is required and when it can be disapplied.

Gladman Developments decision

Gladman Developments challenged an Inspector’s dismissal of an appeal for a large housing scheme (up to 644 dwellings), where the sole remaining reason for refusal was non-compliance with flood risk policy. In treating the absence of a Sequential Test as a determinative – “overriding” – reason for refusal the Inspector erred in law by adopting a rigid approach to national flood risk policy.   

The judgment is clear that even where NPPF policies are expressed in apparently mandatory terms (including footnote 7 policies), they remain material considerations to be weighed under s.70(2) Town and Country Planning Act 1990. A failure to undertake a Sequential Test therefore does not automatically mandate refusal.

The Inspector was required to consider the planning balance – explaining why, on the specific facts, the policy breach constituted a “clear reason” for refusal capable of outweighing the substantial benefits and the absence of any substantive flood harm.

 On the facts, there were good reasons otherwise:

• Although the vast majority of the site lay within Flood Zone 1[1], a very small part fell within Flood Zones 2 and 3[2].

• This led the Inspector to conclude that a Sequential Test was required but has not been undertaken. The Inspector accepted that the scheme posed no unacceptable flood risk, would deliver flood risk betterment (including reduced downstream flooding), and attracted no objection from the Environment Agency or the Local Lead Flood Authority.

• They also acknowledged there would be substantial planning benefits, including significant market and affordable housing delivery in the context of a severe housing land supply shortfall.

For developers, the judgment reinforces that Sequential Test failures are not fatal per se, and that demonstrable flood risk betterment and wider sustainability benefits remain powerful material considerations. For decision-makers, it reinforces the need for a genuinely reasoned, case-specific planning balance; identifying a potential footnote 7 conflict does not displace the statutory duty to weigh all material considerations.

Conclusion

Taken together, the recent updates to national guidance and the Gladman Developments decision confirm that the Sequential Test remains an important policy requirement, but not one that should be applied rigidly or without proper regard to the facts of the case. While the draft NPPF points towards a more structured approach to the application of the Sequential Test, Gladman makes clear that a failure to undertake it is not, of itself, determinative. What matters is whether, on the particular circumstances, that policy conflict genuinely amounts to a clear reason for refusal when weighed against site-specific flood risk evidence and the wider planning benefits. Both developers and decision-makers will therefore need to ensure that flood risk issues are addressed early, clearly and proportionately, and that the planning balance is properly reasoned rather than assumed.

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[1] Lowest level of probability of Flooding

[2] Flood Zones 2 and 3 identify land at medium and high probability of flooding, where development is more constrained and the Sequential Test plays a central role in decision-making