Breach of Condition After Works Have Started: A Guide to Section 73A

Most planning permissions come with a familiar warning: “No development shall commence until…” — followed by a long list of things you’re supposed to do first.

Drainage details, materials samples, ecology reports, Construction Management Plans — the list can be endless.

But in the real world, things don’t always go perfectly to plan. Builders start early. Conditions are overlooked. Designs evolve during construction. Or you simply realise that one of the imposed conditions doesn’t make sense once work is underway.

So what happens if you’ve already started development and then discover a planning condition you can’t meet — or didn’t comply with?

That’s where Section 73A of the Town and Country Planning Act 1990 comes in.

In this article, we’ll look at how Section 73A works, when you can use it, how it differs from the more familiar Section 73 route, and how to handle retrospective appeals when you’ve already broken (or need to change) a planning condition.

What Section 73A actually does

Section 73A gives local planning authorities the power to grant planning permission for development that has already been carried out.

In other words, it allows for retrospective permission. You can apply after the fact to regularise a development or to seek consent for work that didn’t fully comply with your original permission.

While Section 73 (covered in our last article) is about varying or removing conditions before or during implementation, Section 73A is used when development has already happened — with or without compliance.

Typical situations include:

• A condition wasn’t discharged before works began (a breach of a pre-commencement condition).

• The development was built with minor differences from the approved plans.

• A use has operated outside of restricted hours or conditions.

• A condition has proven impossible or unnecessary to meet once works are underway.

The aim of Section 73A is pragmatic: to let planning authorities regularise breaches that don’t justify formal enforcement.

The Act (in plain English)

Section 73A(1) of the Act says that planning permission may be granted for development “carried out before the date of the application”.

That’s the key difference — you’re no longer asking for permission to do something, but permission to have done it.

It means the LPA (or the Planning Inspectorate on appeal) looks at the development as built or operating, and decides whether it would have been acceptable had it been applied for properly at the outset.

Common uses of Section 73A

Although “retrospective planning permission” often sounds negative, it’s surprisingly common and often uncontroversial.

Here are a few real-world examples:

1. Pre-commencement breach
   A housing development begins before a Construction Management Plan is approved. The applicant submits a Section 73A application seeking retrospective approval for a plan that has since been implemented successfully.

2. Built differently from the plans
   A homeowner builds a dormer window slightly larger than approved drawings. The difference is minor, and there’s no increased impact. A Section 73A application regularises the as-built dimensions.

3. Operating outside a restriction
   A takeaway opens until 11pm instead of the permitted 10pm. After demonstrating no noise complaints or amenity harm, the operator applies under Section 73A to vary the condition retrospectively.

4. Outdated condition
   A rural conversion includes a condition requiring a Code for Sustainable Homes certificate, but the code was abolished. Section 73A can be used to remove it retrospectively.

In each case, the goal is the same — to bring a development back into compliance with the planning system.

How Section 73A differs from Section 73

This is a common point of confusion. Both sections involve conditions and flexibility, but they serve different purposes.

Timing:

• Section 73: Used before or during lawful implementation

• Section 73A: Used after development has been carried out

Purpose:

• Section 73: To vary or remove a condition prospectively

• Section 73A: To regularise development that has breached a condition

Effect:

• Section 73: Creates a new permission that supersedes the original

• Section 73A: Creates a retrospective permission covering what's already done

Typical scenario:

• Section 73: Change to design, layout, or operational details

• Section 73A: Breach of pre-commencement condition or as-built variation

Appeal route:

• Section 73: Section 78(1)(a) appeal

• Section 73A: Section 78(1)(a) appeal (retrospective context)

The key distinction is timing: if you’re applying after the fact, Section 73A is your route.

However, both sections can sometimes overlap — for example, when part of a development is built and part remains to be completed. In such cases, LPAs and Inspectors can, and often do, use their discretion to treat it under whichever section best fits the facts.

How retrospective appeals are handled

If the LPA refuses your Section 73A application, or fails to determine it within the statutory period, you can appeal to the Planning Inspectorate under Section 78 — exactly as with any other planning decision.

The Inspector will assess the proposal as built, considering:

• Whether the breach causes harm that would justify refusal.

• Whether the same outcome could have been achieved lawfully via a normal application.

• Whether the condition being breached is still necessary or proportionate.

• Whether granting permission would conflict with local or national policy.

Even in retrospective appeals, the six tests for conditions (set out in the NPPF) remain the benchmark.

A condition should be:

1. Necessary

2. Relevant to planning

3. Relevant to the development

4. Enforceable

5. Precise

6. Reasonable

If the disputed condition fails any of these, you’ll have strong grounds for appeal. For instance, a pre-commencement condition that’s impossible to meet after works begin may no longer be “reasonable” or “necessary.”

If the Inspector allows the appeal, they can issue a retrospective planning permission that authorises the development from that point onward.

Risks and consequences of ignoring a breach

If you discover that development has breached a planning condition, you have three main options:

1. Apply for retrospective permission under Section 73A.
   The safest route — it regularises the breach and avoids enforcement.

2. Seek a Certificate of Lawful Development (LDC).
   Only viable if enough time has passed (formerly 4 years for building works now 10 years, and 10 years for use breaches of condition).

3. Do nothing and hope it goes unnoticed.
   Not recommended — LPAs can issue enforcement notices, stop notices, or injunctions if they believe harm is being caused.

Enforcement can carry significant consequences — including fines, orders to undo works, or difficulties selling or insuring the property later.

Applying under Section 73A shows good faith and can sometimes result in a better outcome than waiting for enforcement action

Combining Section 73A with Section 73

In some situations, you might use both routes together — for example, if you’ve already built part of the development and want to adjust future phases.

The retrospective aspect (what’s already built) can be regularised under Section 73A, while the prospective changes (what’s yet to come) can be varied under Section 73.

Planning Inspectors and LPAs generally accept this blended approach where it helps tidy up complex permissions. The key is ensuring each part of the application is clearly justified and within the scope of the Act.

Good practice for retrospective cases

If you find yourself in a Section 73A situation, here’s how to manage it effectively:

1. Acknowledge the issue early.
   Don’t ignore a breach — even minor discrepancies can snowball into enforcement later.

2. Engage constructively with the LPA.
   Many councils prefer voluntary regularisation over formal action. Provide context and evidence of lack of harm.

3. Submit accurate as-built plans.
   Show exactly what exists on site, including photographs and measurements. Transparency builds trust.

4. Explain the planning merits clearly.
   Justify why the breach causes no harm and would have been acceptable originally.

5. Use professional support.
   A planning consultant can help structure your case and reference relevant policy and appeal precedents.

Common pitfalls to avoid

• Assuming small means safe. Even a “minor” variation can technically breach permission — get advice before works start.

• Failing to link conditions properly. If you secure retrospective consent, ensure necessary conditions are restated.

• Ignoring knock-on effects. Changing one aspect (e.g. materials) might affect others (e.g. design or heritage).

• Delaying action. The longer a breach goes unresolved, the less sympathy you’ll get from the LPA or Inspectorate.

How to appeal a Section 73A effectively

If your Section 73A application is refused, a well-prepared appeal can often succeed where you demonstrate:

• The development causes no material harm;

• The breach was technical or unintentional;

• Enforcement would be disproportionate;

• The condition is no longer necessary or reasonable.

It’s wise to include a planning statement with your appeal setting out:

• The background to the breach;

• The condition’s purpose and why it’s now redundant;

• Policy references and supporting evidence (e.g. noise, highways, design);

• Any relevant case law (e.g. Lawson Builders).

Appeals under Section 73A are often determined by written representations, though hearings are sometimes used for complex cases.

Section 73A may not sound glamorous, but it plays a vital role in keeping the planning system fair and flexible. Without it, countless developments would face unnecessary demolition or enforcement for honest mistakes or reasonable adjustments.

At the same time, it reminds applicants to take conditions seriously. The power to regularise after the fact isn’t a free pass — it’s a safety net for genuine errors, not deliberate shortcuts.

Final thoughts

Discovering that you’ve breached a planning condition can be stressful — especially if you’ve invested time, money, and effort into a project. But it’s rarely the end of the road.

Section 73A exists precisely to deal with real-world situations where developments get ahead of the paperwork. With the right approach, most issues can be resolved sensibly, without conflict or costly enforcement.

The key is to act early, be transparent, and build a clear planning case for why your development remains acceptable in principle and in practice.

If you’re unsure how best to handle a retrospective situation — or whether Section 73A or another route is appropriate — it’s worth getting professional advice from a planning consultant who can help you navigate the process and avoid future risks.

About Me

Andrew Ransome is the planning director at ADP and is a chartered member of the RTPI, with over 22 years of town planning experience.

Andrew has extensive experience offering strategic planning solutions to challenging projects in both rural and urban settings. Follow him on Linkedin.

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