Does the 4 Year Rule Still Apply?

For years, the “4 Year Rule” was one of the most relied-upon principles in planning enforcement. But following changes introduced by the Levelling-up and Regeneration Act 2023, many property owners are asking the same question:

Does the 4 Year Rule still apply?

The short answer is: sometimes — but only in specific circumstances.

This guide explains the current legal position, the transitional rules, common misunderstandings, the enforcement process, and the potential pitfalls you must avoid.

The Legal Position: What Changed?

Under section 171B of the Town and Country Planning Act 1990, time limits restrict when a Local Planning Authority (LPA) can take enforcement action.

Before 25 April 2024

There were two main time limits:

• 4 years for:

  • Operational development (building works)

  • Change of use of a building to a single dwellinghouse

• 10 years for:

  • All other breaches of planning control

After 25 April 2024

The 4-year rule was largely removed. The time limit is now:

• 10 years for virtually all breaches, including:

  • Operational development

  • Change of use to a single dwellinghouse

The Crucial Exception – Transitional Provisions

The 4-year rule still applies if:

• The operational development was substantially completed before 25 April 2024, or

• The change of use to a single dwelling occurred before 25 April 2024

If those conditions are satisfied, and the development has continued for four years, the old rule can still be relied upon.

This is where careful factual analysis becomes critical.

The Role of Lawful Development Certificates (LDCs)

Even where a development has become immune from enforcement through the passage of time, it does not automatically become “lawful” in practical terms. To formalise its status, you will usually need to apply for a Lawful Development Certificate (LDC) under section 191 of the Town and Country Planning Act 1990.

This is a crucial step — particularly if you intend to sell, refinance, or develop the property further.

What Is a Lawful Development Certificate?

An LDC is a legal determination by the Local Planning Authority confirming that the 4-year rule will apply

Importantly:

• An LDC does not grant planning permission.

• It confirms that enforcement action can no longer be taken as 4-years have passed.

• It is determined on legal grounds only, not planning merit.

The authority must assess whether, at the date of the application, enforcement action would be time-barred.

Why an LDC Matters

Relying on the passage of time without securing an LDC can be risky.

An LDC provides:

• Certainty for property transactions

• Comfort for lenders and investors

• Protection against future enforcement

• A clear planning history record

Buyers’ solicitors will frequently insist upon one where unauthorised development is suspected.

The Burden of Proof

The burden rests entirely on the applicant.

You must demonstrate — on the balance of probability — that:

• The breach occurred on a specific date;

• The relevant 4-year period has passed;

• The use or development has been continuous (where required);

• No enforcement action prevents immunity.

The “balance of probability” test means it must be more likely than not that your version of events is correct.

If the authority has no contradictory evidence, and your evidence is coherent and credible, it should grant the certificate. However, weak or inconsistent documentation can result in refusal.

The quality, consistency and chronology of evidence are critical.

The Planning Enforcement Process

Understanding how immunity in planing works requires understanding enforcement procedure and what it means for the 4-year rule

Enforcement Notice

If the LPA believes a breach has occurred, it may issue an Enforcement Notice. This must be served within the relevant time limit (4 years or 10 years, depending on circumstances).

Enforcement Appeal

You may appeal on several grounds, including:

• Ground (d) – the breach is immune because the time limit has expired.

Like with a Certificate of Lawfulness, the burden of proof is on the appellant to provide the evidence to prove the balance of probability.

The “Second Bite” – A Major Overlooked Risk

Many online guides ignore one of the most important enforcement provisions: the “second bite” power under s171B(4).

The “second bite” rule allows a Local Planning Authority to take further enforcement action even after the usual 4-year or 10-year time limit has expired — provided it first acted within that original period. In simple terms, if the council served an Enforcement Notice in time, but that notice was later withdrawn, found defective, or quashed on appeal, it may have a further four years to issue a fresh notice for essentially the same breach on the same site. The first notice effectively “stops the clock”.

This rule can significantly affect both enforcement appeals and Lawful Development Certificate applications.

When considering whether development is immune, the key question may not be whether the normal time limit has passed, but whether the council previously took action in time. If it did, immunity may not have accrued as expected.

Careful review of the enforcement history is therefore essential before relying on the passage of time.

Common Misunderstandings

❌ “After 4 years it becomes legal automatically”

Wrong. The development becomes immune from enforcement, but it remains unlawful unless confirmed through an LDC.

❌ “If it’s a dwelling, it’s always 4 years”

Not anymore. Only dwellings created before 25 April 2024 may potentially rely on 4 years. Anything later is 10 years.

❌ “Continuous occupation is required”

For dwellings, the test is continuous use, not continuous occupation. Vacancy does not necessarily break continuity.

❌ “If 4 years have passed, the Council is out of time forever”

Not necessarily. If enforcement action was previously taken within time, the second-bite provisions may still apply.

Important 4-Year Scenarios Explained

Scenario 1 – Unauthorised Extension Completed in 2022

4-year rule likely applies

A homeowner built a large rear extension without planning permission. The works were substantially completed in March 2022. No enforcement action has ever been taken.

Because the operational development was substantially complete before 25 April 2024, and more than four years have now passed, the old 4-year rule can still apply under the transitional provisions. The owner may be able to apply for a Lawful Development Certificate to formalise immunity.

Scenario 2 – Conversion to a Dwelling in June 2024

4-year rule does NOT apply

A commercial unit was converted into a single dwelling in June 2024 without planning permission.

Because the breach occurred after 25 April 2024, it falls under the new regime introduced by the Levelling-up and Regeneration Act 2023. The applicable time limit is now 10 years, meaning immunity would not arise until 2034 (assuming no enforcement action is taken).

Scenario 3 – Building Started Before April 2024 but Not Finished

4-year rule does NOT apply

A detached outbuilding was under construction in April 2024. The walls were up by 20 April, but the roof and windows were not installed until May 2024.

The key issue is whether the building was “substantially complete” before 25 April 2024. If it was not capable of functioning for its intended purpose by that date, the transitional 4-year rule will not apply. Instead, the development falls under the 10-year rule.

Situations Where the 4-Year Rule Never Applied

• Listed building works (criminal liability)

• Tree Preservation Order breaches

• Relevant demolition in conservation areas

• Most non-residential changes of use

These generally remain subject to 10-year limits (or no time limit in certain demolition or Listed building cases).

So – Does the 4 Year Rule Still Apply?

Yes — but only where:

• The breach occurred before 25 April 2024, and

• It qualifies under the old categories, and

• Four continuous years have passed, and

• No enforcement action interrupts the timeline.

In all other cases, the 10-year rule now applies.

Why Professional Advice Matters

The difference between:

• Substantial completion vs. partial completion

• Change of use vs. operational development

• Vacancy vs. abandonment

• A defective enforcement notice vs. none at all

can determine whether a development is immune — or subject to demolition.

If you believe your development may qualify under the 4-year transitional rules — or if you have received an enforcement notice — early strategic advice is essential.

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.

Get in touch