Planning Gain and Land Value Uplift Tax in the UK: What Landowners Actually Keep
Getting planning permission can multiply agricultural land's value tenfold or more — but Section 106, CIL and capital gains tax all take a share before you see the profit. Here is the full picture.
Why "Planning Gain" Is Such a Significant Figure
The term "planning gain" (or land value uplift) describes the substantial increase in a piece of land's value that occurs when planning permission for development — most commonly residential — is granted. Agricultural land with no development prospects is valued according to its farming productivity; the same land with residential planning permission is valued according to what developers will pay for serviced building plots, which can be dramatically higher.
This gap creates strong incentives for landowners to seek planning permission before selling, and for developers to seek out land with development potential — but it also attracts significant public policy interest in capturing some of that uplift for community benefit, which is where Section 106 and CIL come in.
Section 106 Agreements: Site-Specific Obligations
Section 106 agreements (planning obligations under the Town and Country Planning Act 1990) are legally binding agreements negotiated between the local planning authority and the developer/landowner, typically as a condition of granting planning permission for larger developments. Common obligations include:
| Obligation type | Purpose |
|---|---|
| Affordable housing contribution | A percentage of units (or a financial contribution) allocated as affordable housing |
| Education contribution | Funding towards local school places needed to support new residents |
| Highways/transport contribution | Funding towards road improvements, public transport, cycle infrastructure |
| Open space/green infrastructure | Funding or land provision for parks, play areas, and similar amenities |
| Healthcare contribution | Funding towards local GP surgery capacity in some areas |
These obligations are individually negotiated for each site and development, meaning the financial impact on the landowner/developer's net position varies significantly by location and scheme.
The Community Infrastructure Levy (CIL)
CIL is a more standardised alternative/complement to Section 106, calculated as a fixed rate per square metre of new floorspace, set out in each adopting local authority's published CIL charging schedule (rates vary significantly by area and development type). Unlike Section 106, CIL is generally non-negotiable once the charging schedule is set, though specific reliefs exist (for example, for certain affordable housing, self-build, and charitable development).
Not every local authority has adopted CIL — some rely entirely on Section 106 for developer contributions, so the specific approach (and financial impact) depends on where the land is located.
Worked Illustration (Simplified, Not Site-Specific)
| Stage | Value |
|---|---|
| Agricultural land value (no planning permission) | £10,000/acre |
| Value once outline residential planning permission granted | £400,000/acre (illustrative — actual uplift varies enormously by location) |
| Gross uplift | £390,000/acre |
| Less: Section 106 contributions (illustrative, site-specific) | Reduces net developable value |
| Less: CIL (if applicable, per square metre of floorspace) | Further reduces net value |
| Less: Capital gains tax on the landowner's disposal | 18%/24% of the chargeable gain, after the £3,000 annual exemption |
| Net proceeds retained by landowner | Significantly less than the gross uplift figure, but still typically a very substantial increase over agricultural value |
The precise net figure depends enormously on location, scheme size, negotiated Section 106 terms, applicable CIL rates, and the landowner's specific tax position — this illustration shows the mechanism by which gross uplift is reduced through several layers, not a universal outcome.
Capital Gains Tax vs Trading Income
| Scenario | Likely tax treatment |
|---|---|
| Landowner sells land with planning permission in a single, one-off disposal | Capital gains tax (18%/24% residential rates in 2026/27, £3,000 annual exempt amount) |
| Landowner actively develops the site themselves and sells completed units as an ongoing business activity | HMRC may treat this as trading income, subject to income tax at marginal rates, rather than CGT |
| Landowner enters an "option" or "promotion agreement" with a developer, receiving payments tied to the eventual planning outcome and sale | Tax treatment depends on the specific structure — professional advice essential, as this area involves detailed and fact-specific rules |
The distinction between capital and trading treatment is genuinely one of the more contentious and fact-dependent areas of UK property tax, and getting it wrong can have significant financial consequences — this is not an area to navigate without specialist advice.
Option and Promotion Agreements: An Alternative to Direct Sale
Rather than selling land outright, many landowners instead enter option agreements (giving a developer the right, but not obligation, to buy at a later date, often at a price linked to achieving planning permission) or promotion agreements (where a specialist promoter takes on the planning application process and costs, in exchange for a share of the eventual sale proceeds once permission is secured and the land is sold, typically at auction or by best-price marketing).
These structures can allow landowners to share planning risk with a specialist party while still retaining land ownership until a sale actually completes — but they come with their own complex legal and tax considerations that should be reviewed by a solicitor and tax adviser experienced specifically in land promotion transactions before signing anything.
Frequently asked questions
Related reading
CGT Property Calculator: Selling a Second Home or Rental Property 2026/27
Selling a second home or buy-to-let in 2026/27 means Capital Gains Tax at 18% or 24% on the gain above your £3,000 annual exemption, reported and paid within 60 days of completion. Full worked examples.
Equity Release Interest Roll-Up: How Compounding Interest Eats Into Your Estate
Most lifetime mortgages (the most common form of equity release) charge interest that compounds and rolls up rather than being paid monthly. Here's how quickly that can grow — and what it means for Inheritance Tax and what's left for your beneficiaries.
Garden Rooms, Permitted Development and Tax 2026/27
A garden room or home office pod built under permitted development usually needs no planning permission, but the tax treatment differs sharply depending on whether you use it for a business, rent it out, or add it to a rental property. Here is how it works in 2026/27.