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Understanding the 4-year and 10-year planning rules

Nov 13, 2023

By Laura Potts MRTPI, Planning Consultant, CAD Planning

You may well have heard of these two rules before. Together, they play an important role in our local planning landscape.

Due to legislation that is now in its final stages of passing through Parliament, it seems likely that the 4-year rule will soon be abolished.

This is therefore an opportune time to review these two rules and the implications of the imminent changes.

What is the 4-year rule?

The 4-year rule, formally known as the “4-year rule for immunity from enforcement,” is a provision that grants a degree of legal protection to certain unauthorized developments after a continuous period of four years. This means that if a development has gone unchallenged for four years, it becomes immune from enforcement action by local planning authorities.

The 4-year rule applies to a few different types of developments. Most significantly, it applies to the use of any building (or part of a building) as a dwelling (house or flat). The 4-year rule also applies to most building works, as long as there has been no change in the use of the site.

There are some key points to bear in mind:

· Time Limitation: The 4-year clock starts ticking from the date the unauthorized development is substantially completed or from the date it becomes operational. It is crucial for developers to keep accurate records to establish when the clock began.

· Continuous Use: The 4-year period must be continuous. If there is a break in the use of the development, the clock may be reset, and the immunity from enforcement may be lost.

· Changing Ownership: The 4-year rule can be transferred to new owners. If a property changes hands during the 4-year period, the new owner inherits the time accrued by the previous owner.

· Exceptions: Certain developments are exempt from the 4-year rule, such as those related to mineral extraction or waste disposal. Additionally, developments in designated areas, like conservation areas, may not benefit from this immunity.

· Enforcement: The 4-year rule won’t apply if enforcement action has already been taken against the development.

What is the 10-year rule?

Similar to the 4-year rule, the 10-year rule, or “10-year rule for immunity from enforcement,” extends the protection period to a decade. This rule applies to a broader range of unauthorized developments, allowing a longer timeframe for potential regularization.

Developments subject to the 10-year rule include:

· Most changes of use (except to use as a dwelling)

· Most breaches of planning conditions.

The implications of these rules

Understanding these planning rules is essential for both developers and local communities. For developers, these rules offer a potential avenue for regularizing unauthorized developments, providing a degree of certainty and security. However, it is crucial to navigate the rules carefully, ensuring that all criteria are met.

On the other hand, communities may be concerned about the potential for unauthorized developments to gain legal protection. Striking a balance between facilitating responsible development and preserving the character and integrity of neighbourhoods is a constant challenge for local planning authorities, and one of the key factors driving their decision making.

Important changes are currently in progress

The government is proposing to scrap the 4-year rule. If it is thrown out, all development currently subject to the 4-year rule would become subject to the 10-year rule instead.

This proposal is part of the Levelling Up and Regeneration Bill which is currently making its way through Parliament and appears close to receiving royal assent. Whilst we don’t know the date when this may come into effect, it could be by the end of 2023.

The best advice is therefore to prepare for the 4-year rule’s cancellation.

What might happen when the 4-year rule is scrapped?

One of the key areas of concern around the abolition of the 4-year rule has been the lack of transitional measures in the Bill to protect breaches of planning control that are or will be immune from enforcement on the date on which the new provisions become law. In the absence of these, breaches that would have been immune from enforcement under the 4-year rule would have become susceptible to enforcement action for the remainder of the relevant 10-year period.

However, the government has stated that it will make transitional provisions in regulations to ensure that breaches of planning control that are currently immune from enforcement action will remain immune following the passage of the Bill. That gives some reassurance to those who would otherwise have been adversely impacted.

Play it safe – get expert advice

As can be seen from the above commentary, while the 4-year and 10-year rules sound quite straightforward in principle, they need to be carefully interpreted to ensure that any development does not fall foul of the regulations. It is vital to ensure that your project or development is, as far as possible, protected against any future enforcement action.

At CAD Planning, we have the in-depth expertise needed to help you navigate all the local planning regulations and will guide you carefully through every step of the process. We can assist you in preparing and submitting a Certificate of Lawful Development or Planning Application, depending on the circumstances of the case.

For a no-obligation discussion about your project, get in touch with our expert team at