Skylines vs sunlight: How planning reforms impact rights to light

Recent right to light disputes are set to increase following the relaxation of planning laws by the government last December, particularly in London and other urban areas.

As developers seek to maximise space by building upwards, conflicts with neighbouring property owners over access to natural light are becoming more frequent and complex.

Mustafa Sidki of the construction team at leading Southeast law firm Thackray Williams explores the legal rights, solutions, and actions construction industry specialists can take to navigate this challenging new landscape.

The impact of planning reforms on rights to light

The government’s planning reforms aim to facilitate the construction of 1.5 million new homes by 2030. These changes relax planning restrictions to accelerate approvals for various housing projects. The strategy assigns local councils mandatory housing targets based on available space and existing housing stock, with a nationwide goal of 370,000 new homes per year.

These reforms encourage developers to build upwards in densely populated areas, especially in cities where space is limited. However, this expansion can infringe on neighbouring properties’ right to light.

Understanding right to light

A right of light is an easement to enjoy natural light that passes over someone else’s land and then enters through defined apertures such as windows, skylights and glass roofs into a building.

In practice, a right of light is most often established in accordance with the Prescription Act 1832 which states that if the light has been enjoyed for 20 years, without interruption, the right is deemed absolute and indefeasible unless the right was enjoyed by written consent or agreement.

Once established, a right of light entitles the beneficiary to receive sufficient natural light to allow the room or space to be used for its ordinary purpose. Rooms used for different purposes will be entitled to receive different levels of light, for example, a greenhouse requires more light than a store room.

Assessing an infringement

A reduction in natural light does not automatically constitute an infringement. The key test is whether the loss of light amounts to a nuisance, meaning the affected property is made substantially less comfortable or convenient than before.

Although there is no standard measure of “sufficient light” that can be applied for all uses, there are rules of thumb. The starting point of an assessment to determine loss of light is the principle that the maximum light coming from the sky is the equivalent of 500 lumens per square foot or 500-foot candles. The light from the sky is referred to as the sky factor in the right of light calculations.

An adequately lit room is generally accepted to receive 0.2% of the sky factor over at least half of its area at working plane level (usually at table height). Therefore, a room should have one lumen per square foot over 50% of its floor area.

If a development results in less than half the room receiving a 0.2% sky factor, when it was above this threshold before the development, or where any material reduction occurs in rooms lit to below 50%, a potential claim for infringement of the right of light may well arise.

Legal remedies for right to light disputes

Even if a development has planning permission, it does not override private rights to light. Affected property owners can take legal action in the form of:

• Prohibitory injunction – Sought before construction, this order prevents the development from proceeding
• Mandatory injunction – Applied post-completion, requiring a structure to be altered or demolished to restore light access

The courts often favour injunctions over financial compensation, particularly where light loss significantly impacts the use of a property.

Where an injunction is deemed disproportionate, courts may award financial damages. The level of compensation is assessed using two key valuation methods:

• Diminution in property value – Compensation reflects the decrease in market value due to light loss
• Developer’s gain – A share of the financial benefit the developer derives from the infringement

Mitigating rights to light risks

To manage the risks associated with rights to light, proactive steps can be taken, including commissioning a right to light report early in the planning process. This report will help identify potential claims and inform strategies to mitigate disputes before they arise.

If a neighbouring property’s right to light is likely to be impacted, negotiations can be initiated to secure a deed of release. This legally binding agreement allows the development to proceed in exchange for compensation. The deed must specify whether the release is full or partial and should be registered with HM Land Registry to ensure enforceability.

Another strategy is to use a Light Obstruction Notice (LON) under the Rights of Light Act 1959. A LON creates a notional obstruction that is registered as a local land charge, forcing affected parties to challenge within a year. If they fail to do so, their right to light may be interrupted, effectively resetting the 20-year period required for prescriptive rights.

Where negotiations fail or identifying all affected parties proves difficult, developers may seek indemnity insurance to protect against potential rights to light claims. Such policies cover the costs of legal disputes and compensation payments, but they are generally unavailable once negotiations with affected parties have begun. Therefore, everyone involved in the development must carefully decide whether to pursue an insurance policy or engage in direct negotiations before taking any steps that could affect their options.

Taking advice from a specialist rights to light surveyor and a specialist lawyer is crucial, especially given the more flexible approach to planning permission arising from the government’s reforms.