Planning decisions under challenge: why the best defence starts before permission is granted

Planning litigation is not simply a legal issue. A challenge can delay development, disrupt funding arrangements, increase costs, affect contractual commitments and generate unwelcome publicity. For developers, landowners, funders and public bodies alike, understanding and managing challenge risk should be part of project planning from the outset.

The importance of a pre-decision health check

Many successful challenges do not arise because the planning merits are fundamentally flawed. Instead, they stem from procedural weaknesses.

Before a decision is issued, I recommend carrying out a thorough health check of the process. This should include ensuring there is a clear record of the advice provided by statutory and internal consultees, how that advice was considered and, where appropriate, why any departure from it was justified.

It is also important to check that supporting documents, planning agreement material and background papers have been published in sufficient time to allow meaningful scrutiny. Environmental impacts, including cumulative effects and the consequences of any amendments to the proposal, should be fully assessed, along with any need for further consultation.

Decision-makers should also ensure that proposed planning conditions are necessary, precise, enforceable and reasonable. Most importantly, the officer report, committee minutes and decision notice should provide a coherent and transparent explanation of how the planning judgment was reached.

A well-documented process will not eliminate the risk of challenge, but it can significantly strengthen a party's position if proceedings are brought.

Time is often the greatest challenge

One of the most common mistakes I see is a misunderstanding of the strict timescales involved in planning litigation.

Many planning challenges must be brought within six weeks, although the applicable deadline, trigger date and procedural requirements vary depending on the nature of the decision and the route of challenge. Once a dispute emerges, parties should identify the relevant timetable immediately.

Importantly, pre-action correspondence does not stop the clock. Parties that delay in the hope of resolving matters informally can find themselves facing avoidable procedural difficulties.

Understanding the correct route of challenge

Different decisions are challenged in different ways.

Judicial review is often used to challenge decisions made by local planning authorities. Certain appeal decisions and decisions made by the Secretary of State are commonly challenged through a statutory challenge under section 288 of the Town and Country Planning Act 1990. Other statutory routes exist for particular types of decisions, including some enforcement matters.

This distinction is more than a technicality. Different procedures apply, along with different filing and service requirements. Identifying the correct legal route at the earliest opportunity can be critical.

What the Planning Court will and will not consider

A common misconception is that the court will reconsider the planning merits of a decision. That is not the court's role.

The Planning Court is primarily concerned with lawfulness rather than whether it would have reached a different planning conclusion.

Challenges typically focus on three broad areas.

Illegality involves allegations that a decision-maker misunderstood or exceeded its powers, misapplied legislation or policy, considered irrelevant matters, or failed to take account of legally relevant factors.

Procedural unfairness can arise where statutory requirements have not been followed. This might include defective consultation, failures to reconsult following significant amendments, inadequate publication of documents or other procedural defects.

Irrationality applies where a decision falls outside the range of conclusions reasonably open to the decision-maker. However, simple disagreement over the weight given to planning considerations will rarely be enough.

Additional arguments may involve issues such as apparent bias, legitimate expectation, human rights, environmental law, inadequate reasons or material mistakes of fact.

It is also worth remembering that not every legal error will result in a decision being quashed. The court will consider whether the outcome was likely to have been substantially the same even if the error had not occurred.

Looking beyond the legal arguments

For many clients, the wider commercial implications can be just as significant as the legal issues themselves.

A planning permission may sometimes be implemented while proceedings are ongoing, but doing so carries obvious risks if the decision is later overturned. Delay can affect funding drawdowns, land acquisitions, construction programmes, ecological survey windows and project viability more generally.

Costs are another important consideration. Although costs typically follow the outcome, the position can be influenced by factors such as partial success, duplication of work, unreasonable conduct and, in some cases, Aarhus costs protection. Interested parties should take a proportionate approach and avoid unnecessary duplication of material already being advanced by others.

Five practical steps

When advising on planning challenges, there are five key principles I always encourage clients to follow:

1. Identify the correct challenge route and calculate the deadline immediately.
2. Distinguish genuine public law errors from disagreements about planning judgment.
3. Assess whether any alleged error was actually material to the outcome.
4. Preserve the decision-making record and consider disclosure and candour obligations from the outset.
5. Ensure the legal strategy aligns with wider project, funding, communications and commercial objectives.

Prevention is always better than cure

While every case turns on its own facts, one principle remains constant. The best defence starts long before court proceedings are issued.

Taking time to ensure that consultation has been properly conducted, environmental impacts adequately assessed and decision-making clearly documented can significantly reduce the risk of a successful challenge.

Where concerns do arise, whether before a decision is issued or after proceedings have been threatened, obtaining specialist advice quickly can help organisations protect not only their legal position but also the wider commercial objectives underpinning the project.

Ultimately, successful planning litigation is not just about winning in court. It is about managing risk, maintaining momentum and giving projects the greatest possible chance of proceeding as intended.