Housing land supply and what it changes for applicants

A five year housing land supply position is arithmetic with a great deal of judgement buried inside it, and the judgement is where applications are won. The calculation looks objective. A requirement, a buffer, a list of sites, a trajectory. Each of those four components involves choices, and an authority under pressure to show a supply makes those choices in one direction while an applicant makes them in the other.

What turns the argument from academic to decisive is the consequence. Where an authority cannot demonstrate the required supply, the policies most important for determining the application are treated as out of date, and the statutory balance the decision maker applies changes.

What a supply position is and how it is measured

The calculation compares the number of homes required over five years with the number of homes the authority can show will be delivered on specific deliverable sites over the same period.

Four inputs.

The annual requirement, derived from the adopted plan where it is recent enough, and otherwise from the national method. Which of those applies is frequently the first argument.

The buffer that national policy adds to the requirement, with a larger buffer where delivery has fallen short.

Any shortfall or surplus carried forward from earlier years, and the period over which a shortfall is to be made up.

The supply itself, expressed as a trajectory showing which sites deliver how many homes in which year.

Change any one of those and the headline figure moves, sometimes by more than a year of supply. That is not a criticism of the method. It is why the evidence behind each input has to be examined rather than accepted.

Where the figure is published

Authorities publish an annual position statement, usually with a base date of 31 March or 1 April, setting out the trajectory site by site. It is normally on the planning policy pages rather than with the development management material, and older versions are often left up alongside the current one.

Alongside it sits the authority's annual monitoring report, which gives completions, permissions granted and progress on allocations. Read both. The monitoring report frequently contradicts the supply statement on individual sites, and that contradiction is evidence.

The delivery test result is published centrally by government rather than by the authority, and it is worth checking directly. Practical routes to all of this are set out in finding the published figures.

The consequence of a shortfall

Where the supply falls below the required level, the presumption in favour of sustainable development is engaged for decision taking.

In broad terms that means permission should be granted unless policies in the Framework that protect areas or assets of particular importance provide a clear reason for refusing, or unless the adverse effects of granting permission would significantly and demonstrably outweigh the benefits when assessed against the Framework as a whole. The detail of when the presumption applies repays careful reading, because it is not a grant of permission and it does not disapply the development plan.

Two things follow for an applicant. The weight given to a conflict with a housing supply policy falls. And the benefits side of the balance, including the contribution to supply itself, gains weight. Neither helps a scheme that fails on a protective policy such as Green Belt, heritage or flood risk, where the clear reason for refusal remains available to the authority.

The Housing Delivery Test

The delivery test is a separate measure and it catches different authorities.

It compares homes delivered over a three year period with homes required over the same period, expressed as a percentage. The consequences escalate as the percentage falls, beginning with a requirement to produce an action plan, moving to an increased buffer applied to the supply calculation, and at the lowest level engaging the presumption regardless of the supply position.

Because it measures completions rather than permissions, an authority that grants freely but sees little built can fail the delivery test while claiming a healthy supply. That combination is worth spotting, because it means the presumption applies even where the supply argument would go against you.

Challenging the figures

Successful challenges are almost always site specific rather than methodological.

Work through the trajectory and test each substantial site against four questions. Is there a permission, and is it outline or full? If outline, has a reserved matters application been made, and when? Are there unresolved constraints, such as an access not in the applicant's control, a drainage solution not agreed, or a legal agreement not completed? And is the assumed build-out rate consistent with what a site of that type achieves with the number of outlets proposed?

Lead-in times are the most common weakness. The period from outline permission to first completion on a large site is measured in years, and a trajectory assuming delivery in year two from a site with no reserved matters application is unlikely to survive examination at appeal.

Check for double counting too. A site appearing both as a commitment and within a windfall allowance is counted twice, and windfall allowances themselves need justification from historic evidence rather than assertion.

One further check is worth running before an appeal. Compare the authority's claimed supply against the position it argued at its own local plan examination, and against what it has told inspectors in recent appeals. Authorities are not always consistent between those forums, because the incentives point in opposite directions. A supply argued down at examination and up at appeal, on the same sites within a short period, is a point an inspector will want explained.

Assembling the evidence

For a scheme relying on a supply argument, the Planning Statement should set out the applicant's own position with the same discipline the authority uses.

State the base date. Set out the requirement, the buffer and the shortfall treatment, with the reasoning for each. Present a site-by-site critique of the authority's trajectory, with the source of every challenge. Cite recent appeal decisions in the area where an inspector has reached a view on the same sites, describing them as indicative of how inspectors have approached the question rather than as binding.

And be alert to timing. A supply position can change between submission and determination, and a plan reaching adoption resets the whole exercise, which is why the progress of any local plan examination matters to the programme. Build the case so that it still works if the supply argument falls away, because a scheme resting entirely on a shortfall has nothing left when the shortfall closes.

If you are assembling the wider evidence base, the supporting documents a major application needs should be scoped from the site rather than from a precedent pack.

This is general guidance rather than legal advice. Check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.