The August 2026 National Planning Policy Framework has given HMO Article 4 directions something they have not had before: an express mention in national planning policy.
Policy DM10 now specifically identifies the prevention of an over-concentration of small Houses in Multiple Occupation as an example of when an Article 4 direction may be justified.
That sounds like a major new power for councils. It is not quite that simple. Councils could already use Article 4 to remove the Class L permitted development right from a dwellinghouse to a small HMO. What has changed is the strength and clarity of the national policy support — and, importantly, the wording about how large an Article 4 area can be.
What does DM10 actually say?
The new NPPF was published on 17th August 2026. DM10 says Article 4 directions should be limited to situations where they are necessary to protect local amenity or the wellbeing of the area.
It then gives three examples, including preventing an over-concentration of uses which could affect quality of life, such as small HMOs.
A direction must also:
- be based on robust evidence
- apply to the smallest area required to mitigate the evidenced harm
You can read the August 2026 NPPF on GOV.UK.
HMOs were already capable of being controlled by Article 4
The legal mechanism has not changed. A small HMO occupied by three to six residents normally falls within Use Class C4. In many cases a dwellinghouse in Use Class C3 can change to C4 under Class L without a planning application.
An Article 4 direction can withdraw that permitted development right in a defined area. Once the relevant part of Class L has been withdrawn, where the change from C3 to C4 amounts to a material change of use, planning permission is normally required.
The previous December 2024 NPPF already allowed Article 4 directions in cases where they were necessary to protect local amenity or the wellbeing of an area. HMO directions fell within that general test.
So DM10 has not invented HMO Article 4 directions. The important difference is that national policy now expressly identifies an over-concentration of small HMOs as an example of the harm Article 4 can address.
The Government deliberately strengthened the HMO wording
This was not an accidental reference. During consultation, the Government described DM10 as a more flexible Article 4 policy intended to allow councils to remove permitted development rights where necessary to protect amenity or wellbeing, including where there is an over-concentration of small HMOs.
The final Government response to the NPPF consultation records broad support for the new approach. It also confirms that the final wording was amended specifically to make clearer that an over-concentration of small HMOs can justify an Article 4 direction.
Housing Minister Matthew Pennycook had also told MPs in July that the Government was looking at strengthening national policy in relation to HMOs and Article 4 directions.
Could DM10 support wider or borough-wide HMO Article 4 directions?
This is probably the most interesting part of the change.
The consultation draft referred to the smallest area possible. Some respondents argued that this could be too restrictive where harm exists across a wider area or where restricting one neighbourhood simply displaces the problem elsewhere.
The Government changed the final policy. DM10 now requires a direction to apply to the smallest area required to mitigate the evidenced harm.
That is a subtle but potentially important difference. It does not make a borough-wide HMO Article 4 direction automatically acceptable. But neither does national policy impose an arbitrary maximum size. If an authority wants to cover a large area, the critical question should be whether its evidence explains why that area is actually required to deal with the identified harm.
In other words, the policy may give councils more room to justify a wider direction where the evidence genuinely supports one — but it still requires the geography to follow the evidence.
Borough-wide does not mean evidence-free
We have already seen a number of councils pursuing extensive HMO controls. Bury introduced a borough-wide immediate HMO Article 4 direction, while Havering has proposed a whole-borough direction. Other recent examples include Potters Bar and proposals in Burnley.
DM10 does not remove the requirement for robust evidence. An authority proposing a wide area should still be able to explain:
- what harm or risk it is seeking to address
- how HMO concentration contributes to that harm
- why the chosen boundary reflects the evidence
- why a smaller area would not adequately mitigate the evidenced harm
That could become particularly important where the evidence shows concentrations in only some wards or neighbourhoods but the direction extends much further.
The Planning Practice Guidance has not caught up yet
There is another wrinkle. The current Government Planning Practice Guidance on Article 4 directions still contains wording based on the previous NPPF. It says directions should be measured and targeted and that particularly strong justification is needed where permitted development rights are withdrawn over a wide area.
It also still repeats the old separate test for non-residential to residential Article 4 directions. That part no longer reflects DM10.
The August 2026 NPPF itself says Planning Practice Guidance plays an important but supporting role to national policy. Until the guidance is refreshed, the current DM10 wording should therefore be the starting point.
The older guidance warning about wide areas is not necessarily inconsistent with DM10. Both point towards the same practical requirement: the larger the area, the more important it will be for the authority to demonstrate why that geography is needed.
What DM10 does not do
There are a few things worth keeping clear:
- DM10 does not itself remove Class L permitted development rights anywhere
- it does not make every change from C3 to C4 require planning permission
- it does not mean a planning application for a small HMO should automatically be refused
- it does not replace the legal procedure for making, serving and confirming an Article 4 direction
- it does not remove potential Article 4 compensation consequences where the statutory requirements are met
An Article 4 direction removes a specified permitted development right; it does not turn something that is not development into development. Where a proposal is development and relied on the withdrawn right, a planning application is then required and the merits can be considered against the development plan and other material considerations.
What does this mean for landlords and HMO buyers?
The practical message is that HMO Article 4 directions are likely to remain a popular tool for councils, and DM10 now gives them explicit national policy support.
If you own, buy or are considering creating a small HMO, check our HMO Article 4 map and do not assume that because a property is currently C3 the Class L route will always remain available.
If you are buying in an existing Article 4 area, our guide to buying an HMO in an Article 4 area covers the evidence and lawful-use checks worth making before exchange.
Where a new direction has been announced but is not yet operative, timing can matter. Our guide to what to do when an Article 4 direction is coming in explains some of the practical issues.
The Planning Geek view
The headline is not that councils have suddenly received a new power to control HMOs. They have not.
The change is that the August 2026 NPPF now expressly recognises over-concentration of small HMOs as a legitimate Article 4 concern, while the final wording gives a little more flexibility over the geographical area than the consultation draft proposed.
For councils, that is helpful policy support. For landlords and developers, the safeguard remains the same one running through DM10: robust evidence and an area no larger than is required to mitigate the evidenced harm.
That final requirement may become the important battleground where councils pursue very wide or borough-wide HMO directions.
Official sources
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