Housing supply and housing delivery are related but distinct measures used in the English planning system. Five-year housing land supply looks forward and asks whether an authority has enough deliverable sites to meet its housing requirement over the next five years. The Housing Delivery Test looks backwards and compares the number of homes delivered during the previous three years with the number required. A poor result under either measure can affect how planning applications are decided.

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What is the difference between housing need, supply and delivery?

 

Housing need, housing supply and housing delivery describe different stages of the planning process.

Local housing need is an assessment of the minimum number of homes needed in an area. It is normally calculated using the government’s standard method, which uses existing housing stock as its baseline and applies an adjustment for local affordability.

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A housing requirement is the number of homes that the development plan seeks to provide. It may differ from the local housing need figure where this is justified through plan-making.

Housing supply concerns the sites expected to provide those homes. For decision-making purposes, the principal measure is whether the local planning authority can demonstrate a five-year supply of deliverable housing sites.

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Housing delivery concerns the homes that have actually been completed. This is assessed nationally through the Housing Delivery Test.

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What is a five year housing land supply?

 

A five-year housing land supply is a supply of specific deliverable sites sufficient to provide five years’ worth of housing against the relevant housing requirement, together with the appropriate buffer.

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It is not enough for an authority simply to identify land that might accommodate housing. The sites included in the calculation must be deliverable within the relevant five-year period.

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The calculation provides a forward-looking indication of whether there is a realistic prospect of meeting the area’s housing requirement. It is relevant both to the preparation of local plans and to decisions on individual planning applications and appeals.

 

Which housing figure is used?

 

Where an adopted strategic housing requirement is less than five years old, that requirement will normally be used to calculate five-year housing land supply.

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The same approach may apply where an older strategic housing policy has been reviewed within the previous five years and found not to require updating.

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In other circumstances, the calculation is generally made against the area’s local housing need as calculated using the standard method. This distinction can have a significant effect because the current local housing need figure may be materially higher than the requirement in an older development plan.

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What is a deliverable housing site?

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The National Planning Policy Framework defines what counts as a deliverable site.

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Sites with detailed planning permission should generally be treated as deliverable unless there is clear evidence that they will not be delivered within five years.

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Some other categories of site require clear evidence that housing completions will begin within the five-year period. These include sites with outline planning permission for major development, sites allocated in a development plan, sites with permission in principle and sites identified on a brownfield land register.

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Relevant evidence may include:

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• progress towards the approval of reserved matters and discharge of conditions;

• an agreement with a developer confirming delivery intentions;

• anticipated construction and build-out rates;

• completed site assessment work;

• evidence about ownership, viability and infrastructure;

• funding commitments; and

• a planning performance agreement setting out the route to delivery.

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A planning permission or allocation does not therefore guarantee that every dwelling on a site can be included in the five-year supply. The timing and rate of delivery must also be supported by robust, up-to-date evidence.

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How is five year housing supply calculated?

 

The starting point is normally five years of the applicable annual housing requirement or local housing need figure.

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Any relevant shortfall from earlier years is generally added to the next five-year period. This is commonly known as the Sedgefield approach.

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An appropriate buffer is then applied. The buffer brings forward additional sites from later in the plan period and provides flexibility in case some anticipated development is delayed.

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The buffers are not cumulative. Depending on the circumstances, the applicable buffer is:

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• 5% as the minimum buffer, intended to provide choice and competition in the market for land;

• 20% where housing delivery over the previous three years was below 85% of the requirement; or

• from 1 July 2026, 20% where the authority has a housing requirement adopted within the previous five years, examined against a version of the National Planning Policy Framework published before 12 December 2024, and its average annual housing requirement is less than 80% of its current local housing need figure. This is sometimes described as requiring a “six-year housing land supply”, but the National Planning Policy Framework continues to require a five-year supply with the appropriate buffer. The change may mean that some authorities which could previously demonstrate the required supply are no longer able to do so once the 20% buffer is applied.

 

The resulting requirement is compared with the anticipated number of homes on deliverable sites. The supply is often expressed as a number of years. For example, a result of 4.2 years means that the authority cannot demonstrate the required five-year supply.

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What if an authority cannot demonstrate a five year supply?

 

Where a local planning authority cannot demonstrate a five-year supply of deliverable housing sites, including the appropriate buffer, the policies most important for determining the application are treated as out of date for the purposes of the National Planning Policy Framework.

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This engages the presumption in favour of sustainable development, often called the tilted balance.

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Planning permission should normally be granted unless the application of policies protecting particular areas or assets provides a strong reason for refusal, or the adverse impacts of granting permission would significantly and demonstrably outweigh the benefits when assessed against the National Planning Policy Framework as a whole.

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A housing supply shortfall does not make planning permission automatic. The decision-maker must still consider the development plan, the National Planning Policy Framework and all other material considerations. The shortage of housing land may, however, increase the weight given to the delivery of additional homes.

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What is the housing delivery test?

 

The Housing Delivery Test is an annual measurement of housing delivery in each relevant local planning authority area.

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It compares the total number of homes delivered during the previous three financial years with the number of homes required during the same period. The result is expressed as a percentage.

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Unlike five-year housing land supply, the Housing Delivery Test does not assess whether future housing sites are deliverable. It measures past performance using recorded housing completions.

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What happens when housing delivery falls below the requirement?

 

The policy consequences depend on the authority’s Housing Delivery Test result:

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• below 95%: the authority should prepare an action plan examining the causes of under-delivery and identifying measures to improve delivery;

• below 85%: the authority must also apply a 20% buffer to its five-year housing land supply requirement; and

• below 75%: the presumption in favour of sustainable development applies.

 

These consequences operate concurrently. An authority delivering below 75%, for example, will be expected to prepare an action plan, apply the 20% buffer and apply the presumption in favour of sustainable development.

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The consequences take effect from the day after the Housing Delivery Test results are published and generally remain in place until the next measurement is issued.

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What types of accommodation can count towards supply and delivery?

 

Housing supply and delivery are not limited to conventional newly built houses and flats.

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Net additions resulting from new development, conversions and changes of use may count. Demolitions are deducted when calculating the net increase.

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Purpose-built student accommodation may also contribute. The amount counted generally depends on how much conventional housing it releases or prevents from being occupied by students. Self-contained student studios capable of functioning as independent dwellings may be counted on a one-for-one basis.

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Housing for older people, including some communal accommodation within Use Class C2, may also contribute based on the amount of housing it releases into the wider market.

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Authorities must use the relevant national ratios and avoid double-counting accommodation.

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Why do housing supply figures become disputed?

 

Five-year housing land supply is frequently contested at planning appeals because relatively small changes to the calculation can affect whether the authority has a five-year supply.

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Disputes commonly concern:

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• which housing requirement should be used;

• the base date of the calculation;

• the treatment of previous undersupply or oversupply;

• the correct buffer;

• whether individual sites are genuinely deliverable;

• realistic lead-in times and build-out rates;

• whether infrastructure, ownership or viability constraints have been resolved; and

• the contribution from student, older people’s or other communal accommodation.

 

The published figure is therefore not always conclusive. Its reliability depends on the quality and currency of the evidence supporting each part of the calculation.

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Key points

 

• Housing need assesses how many homes are needed; housing supply identifies where future homes are expected to come from; and housing delivery measures the homes actually completed.

• Five-year housing land supply is a forward-looking assessment of specific deliverable sites.

• The Housing Delivery Test is a backward-looking assessment of completions over the previous three years.

• A 5% or 20% buffer is applied to the five-year supply requirement, depending on the circumstances.

• Failure to demonstrate a five-year supply, or delivery below 75% under the Housing Delivery Test, can engage the presumption in favour of sustainable development.

• A shortfall does not guarantee planning permission, but it can materially affect the planning balance.

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When should professional advice be sought?

 

Housing supply can become central to the strategy for a residential planning application or appeal, particularly where an authority’s published position depends on disputed assumptions about deliverability. Site-specific advice can test the relevant requirement, buffer, shortfall and housing trajectory and explain the weight that should be given to additional housing in the overall planning balance.

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Updated 29 July 2026