An annexe subdivision appeal in Hampshire has been allowed after an Inspector applied the revised National Planning Policy Framework to the separation of an existing country house and its attached annexe. The ruling permits two independent homes at Chalklands, Hatchet Lane, Hatherden, despite the proposal conflicting with Test Valley Borough Council’s older countryside settlement policy.
Inspector R Cahalane issued the decision on 6 November 2026, overturning the refusal of application 25/02464/FULLN. The proposal makes an existing annexe a separate dwelling, with its own curtilage and parking, rather than constructing an additional building in the countryside. The appeal followed a site visit on 15 September.
The case matters because the Inspector gave very limited weight to a restrictive local plan policy, treated the annexe conversion as the reuse of an existing building under national policy S5, and considered the new home not to be isolated. The Inspector also examined the wastewater consequences for internationally protected Solent habitats.
Why the annexe subdivision appeal succeeded
Chalklands sits outside the settlement boundary of Hatherden, identified as a Rural Village in Test Valley’s 2016 Revised Local Plan. Local Plan policy COM2 generally directs housing towards settlements and does not support this new self-contained open-market dwelling. The Inspector accepted the site was in the countryside and concluded that the proposal conflicted with the adopted policy.
The Inspector identified a genuine accessibility problem. Hatherden has a public house and a church, but the routes to them are unlit, lack footways for much of the way and include narrow, winding sections. Future residents of a separate dwelling would rely more heavily on private cars than occupiers of an annexe forming part of the original home. The decision did not dismiss those concerns.
The decisive question for the annexe subdivision appeal was the weight to give local policy against the August 2026 National Planning Policy Framework. Annex A says materially inconsistent development plan policies should receive very limited weight unless examined and adopted, or made, against the current Framework. The Inspector found COM2 more restrictive than national decision-making policy for development outside settlements.
Inspector Cahalane concluded that very limited weight
must be given to the local settlement hierarchy and boundaries governed by COM2. That did not eliminate the statutory development plan from consideration. It changed the weight attached to the conflicting provision when the decision was taken alongside other material considerations.
Reuse of an existing building under policy S5
Under national policy S5, only certain listed forms of development should be approved outside settlements, unless the benefits would be substantially outweighed by adverse effects when assessed against the national decision-making policies. The Inspector found that separating this existing annexe met S5 paragraph 1(c), for the reuse of an existing building, even though creating a separate dwelling required permission for a material change of use.
The annexe was already part of the residential use of the house, and the building was permanent and substantial. There was no proposed increase in size or footprint or external alteration. The Inspector said: I therefore see no reason why the proposal cannot be treated as a reuse of an existing building.
That reasoning gives the annexe subdivision appeal particular relevance to other countryside conversions.
This is not a general permission for rural annexes to become independent homes. The lawful use, physical relationship with the main house and planning consequences of separate occupation must all be examined. Planning Geek’s guidance on building outside a settlement boundary explains the broader policy context for similar proposals.
The group of houses question
Policy S5 also addresses isolated homes. At Chalklands, the Inspector noted Pigeon House Farmhouse, located a short distance beyond the rear garden boundary, and found those properties could reasonably be regarded as a group of houses. A separate pair of houses farther east was divided from the group by undeveloped land.
The proposed home was therefore not isolated for the purposes of the revised Framework, and the separate HO11 test for isolated homes did not apply. The annexe subdivision appeal turns on a precise physical relationship between existing buildings, not merely whether a village boundary line encloses the property. See our guide to isolated homes in the countryside.
The Inspector nevertheless found conflict with policy DP3’s principle of prioritising walking, wheeling, cycling and public transport. There was no evidence of conflict with other relevant national decision-making policies. This meant the accessibility harm still required weighing against the advantages of reusing the existing accommodation without encroachment into undeveloped land.
How the Solent nitrate issue was addressed
Independent occupation would increase the potential number of residents and associated wastewater effects. The Inspector found a likely significant effect on protected Solent European sites, including important habitats for wintering wildfowl, waders and other species. The scheme therefore required an Appropriate Assessment under the Conservation of Habitats and Species Regulations 2017.
The appellant proposed replacing the existing septic tank with a package treatment plant serving both the new and retained dwellings. Evidence put its total nitrogen efficiency at 87% and showed a reduction in the existing site’s nitrogen budget. Following consultation with Natural England, the Inspector concluded the mitigation would avoid an adverse effect on the integrity of the protected sites.
The annexe subdivision appeal was allowed subject to a condition preventing occupation until the specified treatment plant had been installed and brought into use. Its retention and maintenance are also required. The outcome depended on an enforceable solution rather than assuming one extra home would be harmless. Our nutrient neutrality guide sets out the wider requirements.
Housing delivery shortfall carried weight
Test Valley reported only a 2.54-year supply of deliverable housing sites, with a 2025 Housing Delivery Test result of 64%. The Inspector regarded these figures as evidence of housing need. Although one additional dwelling made a modest numerical contribution, the Inspector gave substantial weight to that benefit under national policy HO7.
The proposal also made efficient use of an existing residential building without introducing another structure into the countryside. Against the identified DP3 accessibility harm, the Inspector concluded the housing and reuse benefits would not be substantially outweighed. The Inspector allowed the appeal, notwithstanding its conflict with the development plan considered as a whole.
What annexe owners should take from the decision
The annexe subdivision appeal offers a useful interpretation of how the 2026 Framework can affect older settlement-boundary policies, but it is not a precedent guaranteeing approval elsewhere. The status of the building, the relationship to other houses, transport, housing supply and legally required environmental mitigation all influenced this site-specific conclusion.
Anyone considering a similar project should check the exact wording of S5, the available evidence on lawful residential use and the physical layout before making assumptions about the prospects of consent. Where nutrient impacts arise, a credible and secured mitigation strategy may be critical to whether permission can lawfully be granted.
The appeal was brought by Mr Diplock against Test Valley Borough Council, under planning reference 25/02464/FULLN and appeal reference 6011371. The appeal decision is also available on AppealBase. Its reasoning is best read alongside the current Framework Annex A and the circumstances of the application.
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