How Rights of Light Arise: The 20-Year Rule and Prescription Act 1832

By Daniel Peddlestone · 1 August 2026

Most people first hear about rights of light when a new building threatens to block sunlight to their home or business. But the legal basis for these claims goes back almost 200 years, and understanding how a right of light actually comes into existence is the foundation for knowing whether you have a claim at all.

A right of light is a type of easement. It gives the owner or occupier of a building the legal right to receive natural light through defined openings, typically windows, skylights or glass doors. Unlike most easements, which are created by express agreement between neighbouring landowners, rights of light most commonly arise automatically through long use. This process is called prescription, and it is governed by the Prescription Act 1832.

The core principle is straightforward. If a building has received natural light through a specific aperture for 20 years or more without interruption, a legal right of light is established. Once that right exists, no neighbouring owner can build in a way that substantially reduces the light coming through those openings without the consent of the person who holds the right. You can read more about what a right of light is and how the law defines it.

The 20-year period runs backwards from the date any legal action is brought. So if your windows have enjoyed unobstructed light for at least 20 continuous years up to today, you almost certainly have an established right. The clock does not reset if the property changes hands. It is the building and its apertures that matter, not who owns it at any given time.

There are a few important details worth unpacking. First, the right attaches to specific apertures, not to the building as a whole. If you knock out a wall and install a new window, the 20-year clock starts afresh for that opening. Older, original windows that have been in place for decades will have stronger protection than recently added ones.

Second, the light must have been enjoyed without interruption. Under the Prescription Act 1832, an interruption only counts if it lasts for at least one year and the person enjoying the light has acquiesced to it, meaning they knew about the obstruction and did nothing. A temporary scaffold or hoarding that blocks light for a few months will not break the chain of prescription.

Third, the right can only be acquired against a neighbouring freehold. This is a technical point, but it matters. If both properties are owned by the same freeholder, prescription cannot run because you cannot acquire an easement against yourself. This sometimes catches leaseholders off guard. If you are unsure about whether you can make a claim, it is worth checking the ownership structure early on.

There is also an alternative route. Rights of light can be granted expressly in a deed or transfer, or they can be implied into a conveyance in certain circumstances. However, these situations are less common in practice. The vast majority of rights of light claims rely on prescription under the 1832 Act.

One mechanism that developers sometimes use to prevent a right of light from arising is the light obstruction notice, introduced by the Rights of Light Act 1959. This allows a developer to register a notional obstruction with the Upper Tribunal, which has the same legal effect as physically blocking the light. If the affected property owner does not object within a year, the prescriptive period is interrupted. It is a powerful tool, but it only works if the process is followed correctly and the notice is properly served.

For property owners, the practical takeaway is this. If your building has windows that have received daylight for 20 years or more, you likely hold a right of light. That right exists independently of planning permission, and a developer cannot simply override it by obtaining consent from the local authority. Understanding your legal rights as a property owner puts you in a much stronger position if a neighbouring development is proposed.

If you think a new building could affect the light to your property, the first step is usually to get a specialist surveyor to assess your windows and confirm whether a prescriptive right exists. From there, you can take informed decisions about whether to negotiate, object, or pursue a formal claim. Getting the fundamentals right at this stage makes everything that follows much simpler.

Reference: Prescription Act 1832, Section 3; Rights of Light Act 1959