Hertsmere Borough Council has confirmed its Potters Bar Article 4 Direction controlling the permitted development right from a C3 dwellinghouse to a C4 small HMO. But there is one date everyone dealing with property in Potters Bar needs to keep separate from the confirmation itself: the Direction does not come into force until 6 May 2027.
That means the relevant Class L right remains potentially available until then, subject to the normal GPDO rules and the facts of the particular property. Confirmation in August 2026 did not immediately switch the right off.
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Potters Bar Article 4 is confirmed, but it is not yet operative
The Direction was made on 23 April 2026. Hertsmere then consulted between 6 May and 17 June 2026. The published confirmation notice is dated 12 August 2026, and the council announced on 26 August that the Direction had been confirmed, sealed and approved.
The operative date written into the Direction is 6 May 2027. Until that date, the Article 4 Direction has not withdrawn the relevant permitted development right.
This is a non-immediate Direction. That distinction matters because Article 4 directions can be made so that they take effect immediately, or they can be made in advance with a future operative date. Potters Bar is firmly in the second category.
Exactly which permitted development right is being withdrawn?
The sealed Direction is precise. It removes the permitted development right in Part 3, Class L(b) of Schedule 2 to the Town and Country Planning (General Permitted Development) (England) Order 2015.
Class L(b) is the right for a change from a Class C3 dwellinghouse to a Class C4 house in multiple occupation. C4 broadly covers small HMOs occupied by between three and six residents as their only or main residence, where they share basic amenities.
The Direction does not say that every HMO use is prohibited. It withdraws the planning permission which Class L(b) would otherwise grant for the particular C3-to-C4 change within the mapped area. After 6 May 2027, a relevant C3 to C4 change will therefore require an express planning permission unless another lawful basis applies.
It also does not withdraw Class L(a), which deals with the reverse change from C4 back to C3.
Where does the Direction apply?
The confirmed Direction covers the Potters Bar area shown by the red boundary on Hertsmere’s published map. The council identifies four wards:
- Potters Bar Parkfield
- Potters Bar Oakmere
- Potters Bar Furzefield
- Bentley Heath & The Royds
Anyone buying close to the edge should check the actual map rather than relying on a town name, postcode or estate-agent description. Article 4 control turns on whether the land is within the Direction area.
Planning Geek’s HMO Article 4 map and database has been updated to record Potters Bar as confirmed — operative from 6 May 2027, rather than suggesting the restriction already applies.
Why has Hertsmere introduced the Direction?
Hertsmere says the Direction is intended to give the council greater oversight of the number and concentration of small HMOs in Potters Bar and to allow the planning impacts of proposed conversions to be considered through planning applications.
The council’s consultation material referred to issues such as the concentration and distribution of HMOs, the housing mix and potential effects on neighbourhood character and residential amenity. An Article 4 Direction does not mean a future HMO application must be refused; it means the council gets to assess the planning merits instead of the change proceeding automatically through the withdrawn permitted development right.
Our wider guide explains how Article 4 Directions work and why the exact wording and mapped area always matter.
Can I still use Class L in Potters Bar before 6 May 2027?
Potentially, yes. The Direction has been confirmed, but Class L(b) is not withdrawn in the affected area until 6 May 2027.
That is not the same as saying every property can simply be converted before the deadline. The usual GPDO requirements still apply, and the starting use must genuinely be C3 if Class L(b) is being relied upon. Other planning restrictions, conditions, existing Article 4 directions, enforcement history or the actual planning unit can also affect the answer.
There is another important practical point: permitted development is about the development which has lawfully occurred, not merely a plan to do it. Signing a tenancy, placing an advert, instructing a contractor or deciding to operate as an HMO before 6 May 2027 does not automatically prove that a lawful material change of use took place before the right was withdrawn. In practical terms, a C4 HMO use normally needs at least three occupiers forming two or more households and sharing basic amenities to be living there before 6 May 2027; signed tenancies or an intention to occupy are not enough on their own.
Whether a C4 use has begun is a question of fact and degree. Occupation, the pattern of use and the evidence available will matter. Anyone relying on the pre-operative Class L window should therefore keep proper evidence of the lawful change rather than assuming intention alone is enough.
Would a lawful development certificate help?
A certificate of lawful existing use or development can be valuable evidence where a change has already lawfully occurred. The certificate does not create the use; it certifies the legal position on the evidence before the authority.
If the question is whether a proposed change would be lawful before it happens, a certificate of lawfulness of proposed use or development may sometimes be relevant. Timing still matters, because the legal position can change once the Article 4 Direction becomes operative.
This is one of those situations where buyers and lenders should distinguish between “the seller says it can be an HMO” and documented evidence that the planning position is actually lawful.
Existing lawful HMOs do not suddenly become unlawful on 6 May 2027
The Direction controls future reliance on Class L(b). It does not retrospectively make an existing lawful C4 HMO unlawful merely because the operative date arrives.
So the key due-diligence question for an existing HMO is still whether its present use is lawful. That may be clear from an express planning permission, a lawful development certificate, the planning history or sufficiently robust evidence of the lawful change of use.
Our guide to buying an HMO in an Article 4 area explains why that evidence can materially affect value and risk.
What purchasers, landlords and agents should check now
- check whether the property is inside the confirmed Potters Bar Direction boundary
- confirm the current lawful use rather than assuming a description of “house” or “HMO” settles the planning position
- check the planning history for conditions or earlier decisions which may affect permitted development
- if relying on Class L before 6 May 2027, make sure the change itself can lawfully occur before the operative date
- keep evidence of occupation and use if the timing of a change may later matter
- do not confuse HMO licensing with planning permission: they are separate regimes
- after 6 May 2027, allow for the time, cost and risk of an express planning application for a relevant C3-to-C4 change
This is particularly important on acquisitions completing close to the operative date. A valuation based on future C4 use may look very different if the purchaser has not actually secured a lawful planning route.
Why the advance notice matters for compensation
Class L is one of the types of permitted development specifically dealt with by the Town and Country Planning (Compensation) (England) Regulations 2015. Those regulations sit alongside sections 107 and 108 of the Town and Country Planning Act 1990 and govern the compensation consequences when specified permitted development rights are withdrawn.
A non-immediate Direction can avoid compensation exposure, but the statutory test is more precise than simply asking when the Direction was made or when consultation began. Section 108(3C) of the Town and Country Planning Act 1990 requires notice of the withdrawal to have been published in the prescribed manner not less than 12 months before the withdrawal takes effect. Regulation 4 of the 2015 Compensation Regulations ties that prescribed publication to the Schedule 3 Article 4 procedure, which includes local advertisement as well as the other required forms of notice.
That creates an important issue in Potters Bar. The Direction was made on 23 April 2026 and takes effect on 6 May 2027, but the statutory newspaper notices we have located were published in the Herts Advertiser on 7 May 2026 and the Watford Observer on 8 May 2026. On the face of those dates, the local-advertisement element of the prescribed notice was published less than 12 months before the Direction takes effect.
For that reason, Planning Geek does not think it is safe to state that Hertsmere has necessarily eliminated compensation liability simply by using a non-immediate Direction. There may still be potential compensation exposure in a qualifying case. Compensation is not automatic: broadly, it would require a qualifying planning application for development formerly permitted by Class L to be made within the statutory 12-month period after the Direction takes effect and then refused, or granted subject to more restrictive conditions. The precise outcome could depend on whether Hertsmere can establish that the statutory notice requirements were satisfied at least 12 months before 6 May 2027.
The compensation rules are one reason the timing of a non-immediate Direction matters, but they should not be treated as evidence of Hertsmere’s motive. The council’s published justification is about managing the planning impacts and concentration of HMOs.
See our more detailed guide to Article 4 compensation.
Was the Direction changed before confirmation?
The confirmed sealed Direction published by Hertsmere retains the same core controls described when the Direction was made: the withdrawal of Class L(b) for the mapped Potters Bar area, with the operative date of 6 May 2027. The confirmation notice likewise identifies the same four wards and C3-to-C4 restriction.
I have not found a published change to those operative provisions in the confirmed instrument. For property-level due diligence, however, the sealed confirmed Direction and map should always be treated as the controlling documents rather than an earlier consultation summary.
The dates at a glance
- 23 April 2026 — Direction made and sealed
- 6 May 2026 — consultation opened
- 17 June 2026 — consultation closed
- 12 August 2026 — confirmation notice dated and Direction confirmed/sealed for the future operative date
- 6 May 2027 — Article 4 Direction comes into force and Class L(b) is withdrawn in the affected area
Until that final date, it would be misleading to say simply that “Article 4 applies in Potters Bar”. The accurate shorthand is: confirmed — operative from 6 May 2027.
Official sources
- Hertsmere: Potters Bar HMO Article 4 consultation and documents
- Confirmed sealed Potters Bar Article 4 Direction
- Notice of confirmation
- Hertsmere: Article 4 Direction map
- Hertsmere: confirmation announcement
- GPDO 2015, Schedule 2 Part 3
- Town and Country Planning (Compensation) (England) Regulations 2015
Created: 28th August 2026 — Potters Bar Article 4
