A subject-to-planning conditional contract is a different tool from an option agreement, though the two are often confused because both are used to manage planning risk in a direct property negotiation. In a conditional contract, exchange happens immediately and is binding on both parties from day one. What is conditional is completion, not the commitment to the deal itself: completion only proceeds once a defined planning outcome, usually described as "satisfactory planning permission," has been achieved within an agreed period.
The critical distinction: option versus conditional contract
The difference matters enormously in practice. With an option, the buyer holds a right but never an obligation, if the numbers stop working or planning fails, the buyer simply lets the option lapse and loses only the option fee. With a subject-to-planning conditional contract, both parties are bound from exchange. Once the planning condition is satisfied, neither side can walk away, the buyer must complete and the seller must sell, at the price and on the terms already agreed. A conditional contract therefore gives a seller far more certainty than an option: once the condition is met, the sale is locked in, not merely likely. What it does not remove is the planning risk itself, which sits with whichever party the contract allocates it to, and the timing risk of how long planning takes to resolve.
| Feature | Option agreement | Subject-to-planning contract |
|---|---|---|
| Exchange | No binding purchase obligation | Binding on both parties immediately |
| Buyer's position | Right, not obligation, to buy | Must complete once condition is met |
| Seller's position | Must sell only if option exercised | Must sell once condition is met |
| If planning fails | Option lapses, fee is lost | Contract typically falls away at longstop |
| Certainty for seller | Lower, buyer can walk away freely | Higher, once condition met sale proceeds |
Why "satisfactory planning permission" is the critical drafting point
Almost every dispute that arises from a subject-to-planning contract traces back to how "satisfactory planning permission" is defined. A permission with restrictive conditions, a lower unit count than hoped for, or conditions requiring expensive off-site works might technically be "planning permission" while being commercially unworkable for the buyer. Well-drafted contracts define in detail what counts as satisfactory: a minimum number of units, acceptable use classes, a cap on the value of section 106 or CIL contributions, or specific conditions that would make the permission unsatisfactory if imposed. Vague drafting on this single point is the most common source of later disagreement between buyer and seller over whether the condition has actually been met.
Who pays for the planning application
Responsibility for the cost and practical running of the planning application is a matter of negotiation between the parties rather than a fixed rule. In practice it commonly falls to the buyer or developer, since they control the scheme design, the consultant team, and the strategy for the application, and they are the party best placed to manage that risk. But this is not universal: some contracts split costs, or give the seller input rights in exchange for contributing toward fees, particularly where the seller has a strong view on the outcome or retains an interest in an uplift-sharing arrangement. Anyone negotiating one of these contracts should treat cost and control of the application as points to agree explicitly, not assume a default.
The longstop date and appeal windows
Because planning can take longer than expected, or be refused and appealed, subject-to-planning contracts include a longstop date, a final deadline by which the condition must be satisfied or the contract falls away. Where an appeal route is genuinely likely to be used, the longstop needs to allow enough time for that process, and contracts commonly build in an allowance for a judicial review challenge window, typically around six weeks, on top of the core planning determination period, so that a permission is not treated as final while still open to legal challenge. Getting the longstop date right is a balance: too short and a viable scheme can die on a technicality; too long and a seller is tied up indefinitely.
Why a seller accepts this over a straight sale
A subject-to-planning structure asks a seller to accept delay and planning risk in exchange for two things a straight sale usually cannot offer: a materially higher price, reflecting the uplift in value that planning permission creates, and, once the condition is satisfied, genuine certainty of sale, since both parties are already bound and neither can walk away. Compared to an option, where the buyer can simply let the arrangement lapse, a conditional contract gives the seller more assurance that a satisfied condition converts into a completed sale, which is often the deciding factor for a seller weighing this structure against either an outright sale now or an option agreement instead.
Timing has practical consequences beyond the planning process itself. Because exchange happens immediately in a subject-to-planning contract, the buyer's position and, depending on drafting, potential tax exposure can crystallise well before completion, so buyers typically take specialist tax and legal advice on the structure at the outset rather than assuming the arrangement mirrors a standard purchase timeline. Sellers, in turn, should treat the period between exchange and completion as genuinely committed time: unlike marketing a property openly, a subject-to-planning contract removes the property from any prospect of a competing sale for as long as the condition remains outstanding, which is precisely the trade-off that justifies the higher agreed price.
In practice, well-negotiated subject-to-planning contracts also address what happens if planning is granted but with conditions the buyer considers unsatisfactory, rather than leaving that scenario to be argued after the fact. Common approaches include a right for the buyer to appeal the decision within the option or conditional period, a mechanism for the parties to agree an amended price if a reduced scheme is the only permission achievable, or a straightforward right for the buyer to treat a conditional or reduced permission as not satisfying the contract at all. Deciding which of these applies before exchange, rather than after a permission lands, is what separates a contract that functions smoothly from one that ends up in dispute.
It is worth being clear about what a subject-to-planning contract does not do. It does not remove planning risk from the transaction, it simply allocates that risk between two parties who have already agreed to be bound by the outcome. A seller who wants zero exposure to planning risk should sell outright now at a price that reflects current, unenhanced value. A seller willing to accept some delay and the possibility the deal falls away at the longstop, in exchange for a materially higher price if planning succeeds, is the seller for whom this structure makes sense.
Subject-to-planning in practice: two GalimAI case studies
The Chelmsford land deal case study is a clean example of the structure at work. A direct letter to the owner of a plot on Creekview Road led to a conditional purchase, subject to planning permission, at 330,000 pounds, with the buyer's exposure limited largely to planning costs of around 85,000 pounds. Planning was secured and the site is projected to sell for 900,000 pounds, unlocking a projected return of more than 485,000 pounds while the buyer's upfront capital at risk stayed a fraction of the full purchase price.
The EC1 commercial conversion case study pairs a subject-to-planning condition with an option structure on a B8 storage depot, negotiated directly with a retiring proprietor at a price of roughly 1.3 million pounds against identified market potential of 5.2 million pounds. For how the option side of that combination works, see option agreements explained.
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Can either party walk away from a subject-to-planning contract before the condition is met?
No, not without breaching the contract. Exchange is binding on both parties immediately; only completion is conditional on the planning outcome. This is the key difference from an option, where the buyer has no obligation to proceed at all.
What happens if planning is refused?
The outcome depends on the drafting, but typically the contract falls away if satisfactory planning permission is not obtained by the longstop date, releasing both parties, sometimes with provisions for a deposit or costs to be returned or retained depending on the agreement.
Who decides what counts as "satisfactory" planning permission?
The contract does, if it is drafted well. Precise, objective criteria, unit numbers, acceptable conditions, cost caps on planning obligations, are agreed at exchange, which is why the definition of satisfactory planning permission is the single most important drafting point in this kind of contract.