Land value expectations and viability circularity in plans

Land value expectation is the hinge on which most local plan viability arguments turn. National guidance says the price paid for land is not a justification for failing to comply with plan policy, and it directs that benchmark land value should normally start from existing use value plus a premium to the landowner rather than from a market price agreed in open competition. The reason is a circularity: if the policy burden a scheme can carry is derived from what developers pay for land, and what they pay reflects what they expect to get away with, the policy never bites.

Plans try to cut that loop by setting requirements at plan-making stage on policy-compliant land value assumptions, then treating compliant applications as viable. In practice the loop reasserts itself for several years after adoption, because land bought or optioned under the previous plan is still coming forward.

Why land price adjusts to policy, eventually

Residual land value is what is left after build cost, finance, profit and policy obligations are taken off gross development value. Raise the affordable housing requirement or add a carbon offset and the residual falls, so the price a rational purchaser can pay falls with it. That adjustment is the mechanism the plan-led system relies on, and over a full market cycle it broadly happens.

It happens unevenly. Landowners with no holding cost and no deadline simply wait. Promoters with option agreements signed at a percentage of market value have an incentive to argue the policy down rather than accept a lower price. And a vendor comparing a policy-compliant offer with a historic comparable from the same street will often conclude the lower offer is the bidder's problem.

So adjustment runs on a lag measured in years, not months. Any viability case made in the first three or four years after a plan is adopted sits inside that lag.

The circularity in market-based evidence

A market-value approach to benchmark land value asks what the site would fetch. The difficulty is that transactional comparables embed whatever policy outcome the purchaser expected, including the expectation of negotiating affordable housing down. Using them unadjusted imports the old policy into the new assessment.

Guidance addresses this by requiring market evidence to be adjusted to reflect policy-compliant assumptions, which in principle solves it and in practice produces a dispute about the size of the adjustment. The honest position is that the adjustment cannot be derived from the comparables themselves, because the comparables are the thing being adjusted. It has to be reasoned from the policy difference, and reviewers should expect to see that reasoning rather than a percentage asserted at the end of a table.

Site assembly adds a further distortion. Where a scheme depends on buying in a ransom strip, an access or a neighbouring yard, the price paid includes marriage value: the uplift created by combining interests. That premium is real money and it is also a product of the assembly rather than of the land's existing use, so including it in benchmark land value inflates the baseline and reduces the apparent capacity for obligations. Separate it out and show it as an acquisition cost if you want the figure to survive scrutiny.

How the guidance tries to break the loop

Four devices do the work.

1. Existing use value plus a premium as the default route to benchmark land value, with alternative use value admitted only where there is evidence the alternative is deliverable.
2. Viability testing at plan-making stage, on a typology basis, so that the policy requirements have already been tested for deliverability.
3. A presumption that a scheme complying with up-to-date plan policies is viable, so that an application-stage assessment is the exception.
4. Transparency, with viability assessments published in full, so that the same arguments cannot be made privately to different authorities.

The presumption in favour of compliant schemes being viable is the device most often overlooked by applicants. If you are complying, say so and do not submit an assessment at all, because volunteering one invites a review of figures nobody needed to see.

Options and contracts signed under the old policy

This is the live problem. A promoter holds an option struck in 2021 at ninety per cent of market value with a minimum price, the plan was adopted in 2025 with a higher affordable requirement, and the scheme no longer works at the minimum. The promoter's commercial problem is real. Its planning weight is close to zero.

The reason is structural: the contract is a private arrangement between two parties, neither of whom the planning system owes a return. Treating the minimum price as a fixed input would make every obligation negotiable by the simple expedient of overpaying. Inspectors say this in different words fairly regularly.

What does carry some weight is evidence that no landowner in the relevant market will transact at a policy-compliant price, with the result that allocated sites stall. That is a plan-making argument about deliverability rather than an application argument about one site, and it belongs in a local plan examination or a five-year review, supported by evidence across multiple sites.

Transitional arguments and the weight they get

Transitional claims come in three shapes, with descending success.

The strongest is a timing argument: the application was submitted before adoption, the development plan at the time set lower requirements, and the determination has been delayed by the authority. Section 38(6) of the Planning and Compulsory Purchase Act 2004 still requires determination in accordance with the plan as it stands at the decision date, so this is an argument about weight in the balance rather than a right.

The middle case is a part-built or phased scheme where earlier phases were consented under the previous policy and the later phases are being brought forward on the same masterplan. Consistency arguments have some traction here, particularly where a section 106 already governs the site.

The weakest is pure hindsight: we paid too much. Where a client insists on running it anyway, run it alongside a review mechanism offer instead of in place of one, because a late-stage review gives the authority a way to say yes without conceding the principle. The drafting of those mechanisms matters more than the headline offer, as our note on affordable housing review mechanisms sets out.

Evidence that adjustment has happened

If you are the authority, or you are defending a plan requirement at examination, the evidence that land values have adjusted is specific and gettable. Look for transactions completed after adoption on sites with a known policy position, option agreements renegotiated downwards, allocated sites coming forward at compliant levels, and sale particulars that quote a policy-compliant scheme capacity rather than an optimistic one.

If you are the applicant, the mirror evidence is a record of failed negotiations with named stages and dates, marketing of the site at a compliant price with no offers, and a build cost position supported by a measured estimate rather than a published index applied to a gross area. A Viability Assessment that includes the negotiation history reads very differently from one that presents a single appraisal.

Appeal is where both sets of evidence get tested, and inspectors are willing to reopen inputs the parties thought were agreed, which we cover in when an inspector reopens viability at appeal.

Advising a client mid-cycle

Three practical positions hold up. First, price new acquisitions on the adopted policy and nothing softer, including any emerging requirement at an advanced stage of examination. Second, where a site is already held at an unaffordable price, treat the gap as a commercial loss to be managed through phasing, product mix or a renegotiated option rather than through a planning argument. Third, if an assessment is unavoidable, publish it, keep the inputs conventional, and put the contested judgement in one place where it can be argued about openly.

The uncomfortable part of this advice is that it sometimes means telling a client their land is worth less than they paid. Saying it early costs a difficult meeting. Saying it after an eighteen-month viability dispute costs the difficult meeting plus the fees.

Viability work is a report type where councils expect a suitably qualified author, and professional review is strongly advised before submission. PlanScope drafts the planning narrative and the Affordable Housing Statement structure around a valuer's figures rather than producing the appraisal itself. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval. For specialist technical reports, qualified professional input may be required. See PlanScope pricing if you are budgeting a submission pack.