What the starting price pays for
From £985 we model your scheme and the neighbouring buildings in three dimensions, test the windows that face it against the BRE methods, and write a report that sets out each result in plain words alongside the technical tables.
The figure rises with the number of windows tested. One extension beside one neighbour is a short report; a new block in a street of flats, with dozens of windows to model, is not.
When the council asks for one
National guidance says a report is a validation requirement only if it is on the council's local list, and that list must be recent. Whether yours asks is a matter for its own list, so we check the list before quoting.
Even where not required, a report is sometimes the strongest answer to an objection. If a neighbour says your extension will take their light, a result against the published test ends the argument more quickly than opinion.
What the report is tested against
The reference is the BRE's guide, BR 209, third edition, published in June 2022, which is advisory rather than law. Councils use it as a benchmark and treat departures from it with judgement.
National policy supports the approach: the NPPF asks that development give rise to no unacceptable level of access to daylight and sunlight for neighbouring residents. That is a judgement for the planning officer, and the report supplies the numbers behind it.
London's flexibility
The London Plan says the design of development should provide sufficient daylight and sunlight to new and surrounding housing that is appropriate for its context. The Mayor's Housing SPG adds that an appropriate degree of flexibility needs to be applied when using BRE guidelines, especially in dense areas.
In practice a tight central London street is read differently from a suburban garden. We write the report to the way your own borough applies the guide, and tell you if a scheme is marginal before you go further.
Ordering a report
Tell us the address and send a sketch of the scheme. See our daylight and sunlight report page for what each report contains. If the scheme is not drawn yet, we can prepare the planning drawings first.
The figures, with sources
BR 209
Third edition of the BRE guide to daylight and sunlight in site layout, published June 2022 and advisory only.
Source: RICS Built Environment Journal, 8 May 2024, checked 17 Oct 2026
Policy D6
London Plan clause asking for sufficient daylight and sunlight to new and surrounding housing.
Source: London Plan 2021, Policy D6 part D, checked 15 Oct 2026
Para 1.3.45
Housing SPG says an appropriate degree of flexibility is needed when using BRE guidelines.
Source: Mayor of London, Housing SPG (March 2016, updated August 2017), checked 17 Oct 2026
2 stages
Daylight impacts are assessed by BRE guidance first, then by location and wider context.
Source: GLA, Housing Design Standards London Plan Guidance, June 2023, checked 17 Oct 2026
NPPF P3
Development should not give rise to an unacceptable level of access to daylight and sunlight for neighbours.
Source: National Planning Policy Framework, August 2026, checked 15 Oct 2026
Local list
A daylight and sunlight report is a validation requirement only if it is on the council's published local list.
Source: Planning Practice Guidance, Making an application, checked 15 Oct 2026
Questions
Do I need a report for a small rear extension?
Often not, but it depends on your council's list and your neighbour's windows. We check both in the free look and tell you.
Is the report a guarantee of permission?
No. It supplies measured evidence for the planning officer's judgement; the decision is the council's.
What if the results are poor?
We say so early and show what a small change to height or depth would do, so you can decide before the application goes in.
Do you test our own rooms too?
Yes where the scheme alters them, such as a new rooflight or a deeper room, because the officer can look at both sides.
The fee for daylight and sunlight report
What you get
- A model of your scheme and the surrounding buildings
- Tests of the neighbouring windows it affects
- Results explained in plain words and tables
- Options to reduce any impact that appears
- A PDF to upload with the application
