What the right protects
A right of light is an easement concerning natural illumination through a defined opening, such as a window or rooflight. It is not simply a right to keep an attractive view, nor a guarantee that every part of a garden will remain as sunny as before. The legal and technical assessment concerns the particular protected opening and the relevant right. [3][1]
RICS describes it as a right to a minimum level of natural illumination. A specialist assessment is therefore needed to distinguish an actionable interference from the general observation that a new building will change the available light. [1]
How can the right arise?
HM Land Registry identifies several routes, including an express grant in a deed, implication and prescription through long use. This means the age of the neighbouring building is not the only relevant evidence. [3]
Under the Prescription Act route, 20 years' continuous use can be relevant, but conditions and exceptions apply. For example, written consent and the history of common possession can affect whether a right arises. It is not safe to conclude either that every old window is protected or that every newer window is unprotected. [3]
Ask a solicitor to review the title, relevant deeds and leases, any releases or restrictions, and the factual history of the openings. HM Land Registry's guide also explains that rights or related covenants may need to be considered even where a simple register entry does not answer the whole question. [3]
Planning approval does not settle the private claim
The planning authority considers the public-interest planning effects of development. Government guidance distinguishes those considerations from private rights of light. A planning daylight report and a rights-of-light assessment therefore serve different purposes. [2][1]
The Party Wall etc. Act also expressly preserves easements of light and other easements. A party wall award should not be treated as cancelling a neighbour's separate light rights. [4]
Assess the issue while changes remain possible
Provide the rights-of-light specialist with reliable measured information, the proposed building form and the relevant neighbouring openings. RICS guidance emphasises clear evidence, measured surveys and information that can assist the parties and their legal advisers. [1]
An early assessment can inform a revision to the height, depth or massing before work is committed. That is a project-planning response to an identified risk, not an assurance that any particular reduction will be sufficient. [1]
Remedies are not limited to compensation
Potential outcomes can include an injunction, damages, changes to the design or, in some circumstances, removal of offending work. It is therefore unsafe to budget for a presumed payment and assume the extension can proceed unchanged. [1]
Where a claim is raised, keep the planning documents and private-rights correspondence separate and obtain advice from both a specialist surveyor and a property solicitor. Do not let the planning decision date stand in for a resolved legal position. [1][2]