The new Framework introduces Policy DM8, a national policy dealing specifically with unauthorised development, retrospective planning applications and enforcement.
The Government published a new National Planning Policy Framework (NPPF) in August 2026, replacing the previous version published in December 2024. The August 2026 NPPF introduces significant changes to the way planning applications are considered in England. For property owners dealing with unauthorised development, one change is particularly important: the Framework now includes a specific national policy dealing with unauthorised development, retrospective planning applications and enforcement.
For anyone who has carried out development without the necessary planning permission, discovered that historic works may not have been authorised, or been contacted by their local authority’s planning enforcement team, understanding the new approach is important before deciding what to do next.
One of the most significant changes for retrospective planning cases is the introduction of Policy DM8: Unauthorised Development and Enforcement.
The policy states that when deciding whether enforcement action is expedient, local planning authorities should take account of:
This last point is particularly important.
The fact that development has taken place without the necessary planning permission does not, in itself, determine whether that development is acceptable in planning terms. The council must also consider the actual planning impact of what has occurred.
For example, an unauthorised extension may still need to be assessed in terms of its design, impact on neighbouring properties, character of the area, heritage implications and any other relevant planning considerations.
A breach of planning control and unacceptable development are not necessarily the same thing.
There is, however, an important warning within the new policy.
Policy DM8 states that where retrospective planning permission is being considered, if it is concluded on the evidence that the unauthorised development was intentional, that fact should be given substantial weight when deciding whether planning permission should be granted. The same principle applies where the grant of planning permission is being considered through an enforcement appeal.
This means that the circumstances surrounding the development can be highly important.
There may, for example, be a significant difference between a homeowner who reasonably believed that works did not require planning permission and somebody who knowingly proceeded with development despite being aware that permission was required.
Importantly, the policy refers to a conclusion based on evidence that the unauthorised development was intentional. It should not simply be assumed that every retrospective application involves a deliberate attempt to avoid the planning system.
Where intention becomes an issue, establishing a clear and evidenced history of what happened may therefore form an important part of the planning case.
The August 2026 changes do not mean that retrospective planning applications are no longer possible.
There will continue to be many circumstances where development has taken place without the necessary permission and a retrospective planning application represents an appropriate way of regularising the position.
However, the new policy reinforces the importance of understanding the circumstances of the case before simply submitting an application. Depending on what has happened, the appropriate strategy might involve:
The correct approach will depend on the individual circumstances.
The new Framework also contains potentially helpful provisions concerning how planning applications should be dealt with.
Policy DM3 states that local planning authorities should work with applicants in a positive and proactive manner, seeking solutions to problems where necessary. Authorities should also take a proportionate approach which reflects the scale, complexity and potential impact of the development.
Importantly, councils are expected to consider whether an otherwise unacceptable proposal could be made acceptable through planning conditions or planning obligations. The Framework also states that applications which should clearly be approved should not be refused.
These principles can be particularly relevant to retrospective development. Sometimes an unauthorised development may have a specific problem that can be addressed without requiring everything that has been constructed to be removed.
Depending on the circumstances, changes to windows, additional screening, revised materials, landscaping, alterations to parking arrangements or relatively limited modifications to the development may be capable of addressing the council’s concerns.
A good retrospective planning strategy should consider not simply “Can we defend what is there?”, but also “Could a reasonable alteration significantly improve the prospects of securing permission?”
Another potentially useful provision concerns the amount of supporting information councils can require.
Policy DM2 states that additional requirements contained within local validation lists should only be included where there is a development plan policy requiring the particular assessment. Such requirements should also be proportionate to the scale of the development and its potential impact, rather than being applied equally to every application.
For smaller retrospective developments, this reinforces the principle that the information required to determine an application should be proportionate to the issues actually raised by the development.
That does not mean that evidence is unimportant. In retrospective cases, the right evidence can be decisive. The important point is identifying what information is actually necessary to address the planning issues in the case.
The implementation provisions within the new NPPF are also significant.
Annex A states that the policies within the Framework are material considerations which must be taken into account in decision-making from the day of its publication.
The development plan remains central to the determination of planning applications, but the new national decision-making policies must now be considered alongside relevant development plan policies.
This means that Policy DM8 and the other relevant national decision-making policies are important to retrospective planning cases being considered following publication of the August 2026 Framework.
The August 2026 Framework replaces numbered paragraphs with lettered policy codes. Anyone working from an older planning statement, decision notice or officer report will be looking for paragraph numbers that no longer exist. The table below sets out the policies most often relevant to retrospective planning and enforcement cases.
| Topic | December 2024 NPPF | August 2026 policy |
|---|---|---|
| Unauthorised development and enforcement | No directly equivalent national policy | DM8 |
| Information required to validate an application | Decision-making chapter | DM2 |
| Positive, proportionate determination of proposals | Decision-making chapter | DM3 |
| Weight given to emerging development plans | Decision-making chapter | DM4 |
| Planning conditions and obligations | Decision-making chapter | DM6 |
| Green Belt policy generally | Paragraphs 142–155 | Chapter 13, GB1–GB8 |
| The five purposes of the Green Belt | Paragraph 143 | GB2(1) |
| Inappropriate development and very special circumstances | Green Belt chapter | GB6 |
| Replacement, extension or alteration of an existing building | Paragraph 154 | GB7(1)(b) |
| Grey belt | Paragraph 155 | GB7(1)(g), Annex B |
| Isolated homes in the countryside | Paragraph 84 | HO11 |
| Essential need for a rural worker to live near their work | Paragraph 84 | HO11(1)(a) |
| Design of new development | Paragraph 135 | DP3 |
| Proposals affecting designated heritage assets | Historic environment chapter | HE6 |
| Conservation areas | Historic environment chapter | HE9 |
| When the new policies take effect | — | Annex A |
This table is a practical guide to where the equivalent policy now sits. It is not a substitute for reading the policy itself, and the wording of a number of these policies has changed as well as the numbering.
If you discover that development at your property may not have the necessary planning permission, do not assume that immediately submitting a retrospective planning application is necessarily the best option.
Before deciding how to proceed, it is important to establish:
These questions can materially affect the strategy.
In some cases, a retrospective application will be the appropriate solution. In others, a Certificate of Lawfulness, modifications to the development, negotiation with the council or another approach may provide a better route.
Where the council has already opened an enforcement investigation, obtaining appropriate advice at an early stage can be particularly important.
At Retrospective Planning Experts (RPE), we specialise in resolving retrospective planning and enforcement matters.
Our role is not simply to prepare and submit a retrospective planning application. We first assess the circumstances of the development, its planning history and status, the available evidence, relevant local and national planning policies, and the prospects of securing permission.
We can then identify the most appropriate strategy for resolving the matter.
Where a retrospective planning application is the right approach, we work to build the strongest planning case available. Where another route may be more appropriate, we explain the alternatives and the potential risks before you proceed.
The introduction of Policy DM8 makes this strategic assessment particularly important. The question is not simply whether a retrospective application can be submitted, but how the unauthorised development should be approached, what can be evidenced and which strategy offers the best prospect of resolving the situation.
If you have carried out development without planning permission, discovered an historic planning issue with your property, or have been contacted by your council’s planning enforcement team, RPE can assess your case and advise on the most appropriate next steps.