Rights of light surveys alongside a planning application

Rights of light and planning daylight are two separate systems that happen to involve the same sunlight. Planning asks whether the effect on neighbours is acceptable in the public interest. A right to light is a private property right, enforceable in the courts by injunction, and a planning permission is no answer to it. Developers who discover that order of events late tend to discover it after the frame is up.

So the practical rule is to run the rights of light analysis at feasibility stage, before the massing is fixed and long before the planning application is submitted. The two assessments use different methods, different thresholds and different remedies, and only one of them can stop a building that already has permission.

What a right to light protects

A right to light is an easement. It attaches to a defined aperture, a window or a glazed opening, in a particular building, and it entitles the owner of that building to receive light through that aperture.

Three features of the right catch developers out. It protects apertures, not land, so there is no right to light over a garden, a yard or an open car park. It protects a quantity of light sufficient for the ordinary use of the room, not all the light currently enjoyed. And it belongs to the owner of the benefited land, which may be a long leaseholder rather than the freeholder you negotiated with.

The right can arise in three ways: by express grant in a deed, by implied grant on a sale of part, or by prescription through long use. Prescription is the common one in practice.

The legal test against the planning test

The legal test is whether the interference leaves the room with insufficient light for the ordinary purposes for which it is used, following the approach the House of Lords took in Colls v Home and Colonial Stores. That is a nuisance test, not a percentage reduction test.

The conventional method for measuring it is the Waldram approach, which assesses whether at least half the area of a room receives a sky factor of 0.2 per cent at a working plane 850 millimetres above the floor. A room meeting that test is treated as adequately lit, and the question becomes how much of the adequately lit area is lost.

The methods disagree often enough to matter. A scheme that passes the planning tests comfortably can still cause an interference to one window that is enough to sue on in one neighbouring room, and the converse happens too. For the planning side, a Daylight and Sunlight Assessment applying the recognised benchmarks is what the authority will expect, and councils usually expect a suitably qualified author with professional review before it is relied on.

Both assessments are increasingly being run with modern modelling rather than hand methods, and the Waldram approach has been criticised for decades as a crude representation of real daylight. Courts have been willing to look at other evidence, but the convention retains its grip, partly because the body of settled valuations is built on it.

Prescription and twenty years of enjoyment

Under the Prescription Act 1832, a right to light can be acquired by twenty years of uninterrupted enjoyment of light through the aperture. There is no need to show any agreement, and the right attaches regardless of what the neighbouring owner intended.

Four points for a development appraisal:

• The twenty years runs to the date proceedings are brought, not to the date you apply for permission.
• Alterations to the aperture can affect the right. A window replaced in the same opening generally keeps it. A window moved or substantially enlarged may not, at least for the new part.
• New buildings start a new clock, which is why a recently completed neighbouring block may have no right at all.
• Interruption of the light for a year or more can defeat the accrual, which is the mechanism the Rights of Light Act 1959 turns into a formal procedure.

That 1959 Act allows a notice to be registered as a local land charge, operating as a notional obstruction. It is a tool for preventing a right from maturing rather than for removing one that exists, and it has to be used before the twenty years are complete.

Injunction risk and when it bites

The remedy is what makes this subject expensive. Courts can award damages, and usually do, but they retain the power to order a mandatory injunction requiring a completed building to be cut back. That happened in HKRUK II (CHC) Ltd v Heaney, where floors of a finished building were the subject of an injunction, and the case changed the way developers price the risk.

The position was then softened by the Supreme Court in Coventry v Lawrence, which restored a broader discretion to award damages in lieu of an injunction rather than treating the injunction as the starting point. The result is genuine uncertainty. An injunction remains possible, particularly where the developer proceeded with knowledge of the objection, and the conduct of the parties carries real weight.

Three factors raise injunction risk: carrying on after a letter before action, refusing to engage with a reasonable release negotiation, and designing a scheme whose profitability depends on the infringing floors. Three factors lower it: early engagement, a documented attempt to design out the interference, and a without prejudice offer that reflects a defensible valuation.

Damages are assessed either on a book value basis, by reference to the loss of amenity, or on a negotiating basis, by reference to a share of the development profit attributable to the infringement. The second approach produces much larger numbers, and it is the one a well advised neighbour will argue for.

Release agreements, insurance and statutory override

Three routes manage the risk commercially.

A deed of release is the cleanest. The neighbour agrees, for a payment, to release or vary the right so far as the scheme requires. Scope it to the consented drawings and add a mechanism for amendments, because a scheme that changes after the deed is signed may fall outside it.

Insurance is the fallback where a neighbour cannot be found, will not engage, or where the number of affected interests makes negotiation impractical. Policies respond to the cost of defending a claim and to the damages or cutback cost. Underwriters will want the surveyor's analysis and evidence that you have not approached the beneficiaries, since an approach can make the risk uninsurable.

The statutory override is the strongest tool and the least available. Where land has been appropriated for planning purposes by a qualifying authority, section 203 of the Housing and Planning Act 2016 allows development to interfere with easements, with compensation payable instead of an injunction. It requires the authority's involvement and a proper statutory process, and it is used on regeneration schemes rather than on ordinary infill.

Why planning permission is no defence

This is the point worth repeating to clients. A planning permission authorises development in public law. It does not transfer, extinguish or override a private property right, and the grant of permission is not a licence to commit a nuisance.

Nor does the authority have a duty to protect private rights when it determines an application. Officers will sometimes add an informative noting that other consents or rights may be affected, and that informative is the full extent of the planning system's interest.

The same logic applies to the construction phase. Scaffolding, hoardings and temporary works can interfere with light and with other rights, and the planning position says nothing about them, which is why temporary loss of daylight during construction needs handling separately from the permanent assessment.

Sequencing the two assessments

Run them in this order and the risk stays manageable:

1. At feasibility, commission a rights of light appraisal on the massing envelope. Identify every aperture with a potential right and the scale of the interference.
2. Test design options against both the legal test and the planning benchmarks before fixing the massing.
3. Decide the commercial strategy: design out, negotiate releases, insure, or accept a priced risk.
4. Prepare the planning daylight and sunlight evidence for submission, including an Overshadowing Study where amenity space is affected.
5. Start release negotiations on a timetable that does not collide with the planning decision, so you are not negotiating under the pressure of a committee date.
6. Review the position after any design change, including amendments made to satisfy the authority.

Step two is the one that pays. A floor removed at feasibility costs a drawing revision. The same floor removed under an injunction costs the floor.

Read the adopted policy wording too, because how local plan amenity policies use BRE 209 varies between authorities and determines what the planning case has to prove.

Browse the report types on PlanScope to see which daylight and amenity documents your scheme is likely to need for the planning application.

This is general guidance, not legal advice. Rights of light turn on title, apertures and the facts of each case, so take advice from a qualified surveyor and a solicitor before relying on any of it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.