Affordable housing contributions for small sites
The Local Plan Partial Review was adopted on 4 March 2026.
The review introduced a new affordable housing contribution for small residential developments.
Implementation date
Affordable housing contributions for small sites will apply to all applicable planning applications validated after 11.59pm on 28 July 2026.
Which developments are covered
The Local Plan Partial Review introduced a new affordable housing contribution of £50,000 per dwelling on sites providing 1 to 9 dwellings (gross).
It applies to all dwellings including:
- Non-self-contained dwellings
- Self-contained dwellings
The requirements are set out in Policy LP23 of the Local Plan Partial Review.
Validation requirements
Validation dates are different to the date an application is received.
For an application to be validate, it must meet the requirements set out in the Local Validation Checklist. We will confirm when an application has validated.
Outstanding information could mean your application has been received but not validated, so you should make sure you understand the checklist requirements before submitting an application.
Unilateral undertaking
The affordable housing contribution is a planning obligation secured by a formal legal deed called a 'unilateral undertaking', signed by the parties giving the obligations or by agreement.
The unilateral undertaking contains covenants (planning obligations) that set out what the landowner agrees to do, or not do, and when these obligations must be met. It also includes a plan showing the land to which it relates.
Submit a draft unilateral undertaking
Use our unilateral undertaking template and submit your draft unilateral undertaking to your planning officer, with:
- An application site plan
- A copy of the Land Registry title documents covering the entire application site
- A covering letter confirming that our legal costs for approving and registering the agreement, and any monitoring fees, will be met
If our template is not used, additional legal costs may be incurred to ensure the draft unilateral undertaking meets our requirements.
Return the completed undertaking
After you submit the draft unilateral undertaking, the planning officer will contact you with any amendments that need to be made before it is signed by the parties.
Once all parties have signed the unilateral undertaking, return the following to your planning officer:
- The signed unilateral undertaking
- One cheque payable to the London Borough of Wandsworth to cover the legal and monitoring fees