Small sites in London and the policy presumption
The small sites presumption only operates where the scheme matches the listed development types and meets the design standards. What qualifies, what gets refused, and the documents a small London application needs.
The small sites policy in the London Plan 2021 asks boroughs to apply a presumption in favour of small housing developments on sites below 0.25 hectares. That is the headline, and it is weaker in practice than it sounds, because the presumption only operates where the scheme does the things the policy lists: infill, small scale redevelopment, intensification within walking distance of a station or town centre, conversion, or the use of mews and backland land, and where the design meets the Plan's design led standards.
So the presumption is conditional. A poorly designed backland scheme on a quarter of a hectare gets no benefit from it at all.
What the small sites policy says, and which sites it covers
Policy H2 sets the size threshold at below 0.25 hectares. Above that, the scheme is assessed under the Plan's general housing and design policies without the presumption.
The development types the policy supports:
- Infill of gaps in an existing frontage
- Small scale redevelopment of an existing building or buildings at higher density
- Incremental intensification of existing residential areas within reasonable walking distance of a station or town centre, or in areas with reasonable public transport access
- Conversion or subdivision of existing buildings into more homes
- Development of mews, courtyards and backland sites
- Homes above or alongside existing non residential uses
Each borough also has a small sites housing target in the Plan, which gives a policy reason for support that officers will recognise even where a local plan is older and less supportive.
The practical consequence for a self builder is that the policy case is worth stating explicitly in the application. Many small London applications are submitted with no reference to it, and the officer then assesses the scheme purely against borough policy.
The presumption and how boroughs apply it
Boroughs apply it unevenly, and it is worth understanding why rather than being surprised by it.
Some have adopted small sites guidance that sets out what they will support, including typologies and design standards. Those boroughs are the easiest to work with, because the expectations are written down.
Others resist intensification in suburban areas where local opposition is strong, and they rely on borough design and character policies to do so. In those boroughs the presumption still applies, and the argument becomes whether the scheme meets the design standards the presumption is conditional on.
What this means in practice:
- Read any adopted borough small sites guidance or design code before sketching anything.
- Check whether the site sits within the Plan's intensification criteria, which depend on public transport access and proximity to a station or town centre boundary.
- Establish the borough's small sites target position, since a borough behind on delivery has a weaker case for refusal.
- Treat the design standards as the test, because that is where the application will be decided.
Design quality expectations on an infill plot
Design is where the presumption is earned. The Plan expects a design led approach to site capacity, meaning the quantum of development is derived from what the site can accommodate well rather than from a target density. That reasoning is set out in the design led approach to optimising site capacity.
What officers look for on a small infill plot:
- A plot width and building line that respond to the existing rhythm of the street, rather than a building squeezed between two others
- Roof form that relates to the neighbours, including eaves and ridge heights taken off a measured survey
- Materials drawn from the immediate context, specified rather than described
- Window positions that avoid direct overlooking, with the geometry demonstrated
- Refuse and cycle storage designed in, not added as a bin cupboard in the front garden
- Private outdoor space for each home
Submit a site section through the plot and both neighbours. More small London applications are refused for the relationship in section than for anything visible in plan.
Backland and garden land sensitivities
Backland development attracts the most objections and the most refusals, and there are three recurring reasons.
Access. A new home reached by a long narrow drive past neighbouring gardens generates noise and headlight disturbance, and the access often cannot accommodate refuse and emergency vehicle requirements. Check the borough's refuse vehicle access standards before the layout, because retrofitting a turning head rarely works.
Overlooking in two directions. A backland plot is usually surrounded by rear gardens, so a two storey house overlooks several properties at once. Single storey, or a one and a half storey form with roof lights rather than dormers, often succeeds where a two storey house does not.
Garden land status. Residential gardens are excluded from the national definition of previously developed land, so a garden land scheme cannot claim brownfield status. That does not make it unacceptable, and it does remove one argument applicants often try to use.
Trees are the fourth issue in practice. Mature trees in rear gardens are frequently protected, and a layout that sits inside root protection areas will not be supported.
Amenity standards that still bite
The presumption does not relax the Plan's housing quality standards, and these are the most common cause of a refusal on a scheme that is otherwise acceptable in principle.
| Standard | Requirement |
|---|---|
| Internal floor area | Nationally described space standards by bedrooms and occupancy, for example 37 m² for a one bedroom one person dwelling and 50 m² for one bedroom two person |
| Private outdoor space | A minimum of 5 m² for one and two person dwellings, with additional area for each further occupant |
| Aspect | Dual aspect preferred, with single aspect north facing homes avoided |
| Floor to ceiling height | At least 2.5 m for a substantial proportion of the dwelling |
| Accessibility | A proportion of homes built to the higher accessibility standards under the Building Regulations |
Daylight to both the new homes and the neighbours is assessed against the current BRE guidance, and in dense urban situations the targets need careful handling, which we cover in BRE 209 daylight guidance in dense London.
Where a basement is proposed to gain floor area, expect the borough to require assessment of ground conditions, groundwater and structural effects on neighbours, which is the territory of the Basement Impact Assessment. Many boroughs have specific basement policies with their own limits on extent and depth.
Transport and parking evidence at this scale
In areas with good public transport access the Plan expects car free development, and a car free scheme is usually easier to approve than one with parking. Where the street has controlled parking, the borough will often require a section 106 undertaking that occupiers cannot obtain a residents permit.
Cycle parking standards are specific and frequently missed on small applications: long stay provision of two spaces for dwellings of two bedrooms or more, and one space for studios and one bedroom homes, in secure, covered and accessible storage. A shed in a rear garden reached through the house does not meet the accessibility expectation.
For most small sites, a short transport statement covering access, visibility, refuse collection, cycle parking and any parking survey evidence is enough. A full transport assessment is not expected below the Plan's thresholds.
Documents a small London application needs
A typical pack for one to four homes on a small site:
- A Planning Statement setting out the small sites policy case, the borough policy position and the response to likely objections
- A Design and Access Statement with a measured survey, site sections through both neighbours, and a materials schedule
- A daylight and sunlight assessment where neighbouring windows are close or the plot is tight
- An arboricultural impact assessment where trees are on or adjacent to the site
- A drainage strategy with sustainable drainage measures and the discharge rate
- A biodiversity net gain assessment and metric calculation, prepared by a competent person under the Environment Act 2021 regime
- A transport statement covering access, refuse and cycle parking
Opportunity area frameworks can add further expectations where the site falls within one, as we set out in what an opportunity area allocation changes.
One honest uncertainty. The London Plan 2021 is the adopted strategic plan at the time of writing and the Mayor has powers to review it, so confirm the current wording of Policy H2, the size threshold and the borough's small sites target before relying on them.
Enter your postcode on PlanScope to see which documents a small London site is likely to need.
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.
Frequently asked questions
What size counts as a small site in London?
Policy H2 of the London Plan 2021 applies to sites below 0.25 hectares. Above that threshold the scheme is assessed under the Plan's general housing and design policies without the presumption. Measure the site area carefully, since including or excluding an access strip can move a scheme across the threshold.
Does the presumption mean my scheme will be approved?
No. It is conditional on the scheme falling within the development types the policy lists, such as infill, small scale redevelopment, intensification near a station or town centre, conversion, or mews and backland development, and on the design meeting the Plan's design led standards. A poorly designed scheme gains nothing from it.
Is a garden considered brownfield land?
No. Residential gardens are excluded from the national definition of previously developed land, so a garden land scheme cannot claim brownfield status. That does not make the scheme unacceptable in principle, and it removes an argument applicants often try to use. The scheme has to succeed on design, amenity and access instead.
Why are backland schemes refused so often?
Three reasons recur: an access drive running past neighbouring gardens that generates disturbance and cannot meet refuse or emergency vehicle requirements, overlooking in several directions at once because the plot is surrounded by rear gardens, and protected trees whose root protection areas conflict with the proposed layout.
What cycle parking is required for a small scheme?
London Plan standards expect long stay provision of two spaces for dwellings of two bedrooms or more and one space for studios and one bedroom homes, in secure, covered and accessible storage. A shed at the end of a rear garden reached through the house is unlikely to meet the accessibility expectation, so design the store into the layout.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.