The National Planning Policy Framework (August 2026) introduced a new decision-making policy which has the potential to significantly impact the determination of retrospective planning applications. Whether this policy applies to a particular application is likely to turn on how decision makers interpret the requirement that unauthorised development was ‘intentional’.
The new policy on intentional unauthorised development
Policy DM8(2) concerns unauthorised development and enforcement. It states:
‘In case of unauthorised development where consideration is being given to an application for retrospective planning permission (or through an enforcement appeal, whether to grant planning permission in respect of a breach of planning control), if it is concluded based on evidence that the unauthorised development was intentional, that fact should be given substantial weight in considering whether to grant planning permission.’
What does ‘intentional’ mean?
On first reading, this test appears relatively straightforward: where the evidence shows that unauthorised development was intentional, this fact should be given substantial weight in the planning balance. However, such a reading is not considered practical.
Nearly all development is completed intentionally – it would be highly unusual for an extension to be constructed or a barn to be converted entirely by accident. A strict and literal reading of the policy is therefore unlikely to be sustainable. It would require substantial weight to be given against almost every retrospective application, leaving the reference to intentionality with little practical purpose. If the policy were intended to penalise retrospective applications generally, it would have directed decision makers to give substantial weight to the fact that permission was sought only after the development had taken place.
A more practical interpretation is that the policy is directed at cases involving a deliberate breach of planning control, rather than merely the deliberate carrying out of the development itself. This may be a difficult test to satisfy; the evidence would need to demonstrate that the developer knew the development would breach the planning regime and deliberately carried on regardless.
Can intention be demonstrated?
Demonstrating intention requires a high evidential burden to be discharged. It cannot be assumed the developer knew (or ought to have known) that their development would breach the planning regime. Instead, decision makers will consider whether the evidence demonstrates the developer knew their actions would be in breach. The decision maker could ask:
- Did the local planning authority write to the developer before the works commenced, informing them they would breach the planning regime if they continued the project?
- Was the developer refused planning permission for the development but completed the works regardless?
- Did the developer proceed after receiving professional advice that planning permission was required?
Contrastingly, there are circumstances where a developer can reasonably argue they thought the development was not a breach of the planning regime.
- The development was very similar to a permitted development right, such that the developer could reasonably believe they benefitted from the right when completing the works.
- The development is a deviation from an approved permission, of such scale that the deviation was not identified by the developer until after the works were completed.
- The developer obtained professional advice before commencing works that planning permission was not required.
Practical implications for retrospective applications
Whether DM8(2) and the associated ‘substantial weight’ apply to a retrospective planning application could alter the outcome of the application significantly, potentially tipping the balance away from approval and towards refusal. The question of whether a development was carried out intentionally may therefore become a key issue in retrospective applications and enforcement appeals.
Developers and landowners should not assume that a local planning authority’s assertion of intentionality will withstand scrutiny. The policy requires an evidence-based assessment, and in many cases the factual position may be far more nuanced than initial enforcement correspondence suggests. Careful analysis of the planning history, contemporaneous advice, communications with the authority and the circumstances surrounding the development may all be relevant.
If you are considering a retrospective planning application, have received enforcement correspondence, or are involved in an appeal where DM8(2) may arise, obtaining specialist planning advice at an early stage can help identify and address these issues before they materially affect the outcome of your case.