Rights to light: chasing shadows

Posted: 22/01/2024

Rights to light are often seen as a dark art. Yet they can be a fundamental – and sometimes decisive – factor in urban development, which some developers have learned to their cost.

The area is complex and constantly evolving, and each site is different, so the advice of specialist surveyors, valuers and lawyers should always be sought.

What are rights to light?

They are a form of easement by virtue of which a property is entitled to receive sufficient natural light to the apertures (which are ordinarily windows) in a building through the airspace of another property that is not in the same ownership.

In anachronistic legal terms, the property with the rights to receive light and the property over whose airspace those rights are exercised are respectively known as the ‘dominant tenement’ and the ‘servient tenement’. But this article will refer to the former as the ‘impacted building’ and the latter as the ‘site’ for simplicity.

How do they arise?

It is uncommon but not unknown for rights to light to be created expressly by deed or to be implied, usually where a site and an impacted building were in the same ownership and one was sold or let.

They can also arise by prescription where light has been enjoyed by an impacted building over a site for a long enough period. Originally that must have been since before the year 1189, although the courts later developed the doctrine (or fiction) of lost modern grant. This means that where light can be shown to have been enjoyed for any continuous period of at least 20 years without force, secrecy or permission then it is presumed the rights to the light were granted by a deed that has been lost unless there is evidence to the contrary.

The most frequently encountered rights are those arising under the Prescription Act 1832. Unlike the forms of prescription mentioned, these may be acquired by a leaseholder as well as a freeholder of an impacted building, and they accrue where light has been enjoyed without written consent for 20 years. But they only come into being where legal proceedings are commenced to enforce or challenge that enjoyment and it must continue uninterrupted until then. That and the fact that only an interruption of at least a year counts can create considerable scope for error and dispute.

How are they identified?

The first step is for a rights to light surveyor to model the impact of a development on the surrounding buildings and determine which may have rights over the site. Historic research may be required as the surveyor will need to take account of the fact that rights may still exist where former apertures have been closed (as it is difficult to show that a right has been abandoned) or replaced (as rights may transfer to new apertures).

While most rights to light will not be formally documented, legal due diligence also remains important in establishing if there are any express rights or potential for implied rights that benefit an impacted building, or if any rights may have come to an end.

This may be the case where rights were surrendered in connection with a previous development of the impacted building (as it is not unusual for there to be a mutual release of rights) or, indeed, the site. And it will reveal whether the light to an impacted building is enjoyed by consent or if the developer has rights to carry out the development notwithstanding any reduction in light to the impacted building.

A more detailed assessment would then be undertaken in relation to the effect of the development on the impacted buildings identified. This is not a straightforward task, even with the aid of computer modelling, since assumptions may need to be made, or further investigations carried out, as to the layout of the rooms behind the apertures in the impacted buildings and the uses to which they are put.

What is an infringement?

Identifying that a development may negatively affect the light reaching an aperture in an impacted building does not necessarily mean that there will be an infringement of rights.

The legal test is whether it amounts to a nuisance, and that depends on whether the resulting natural light in the room behind the aperture is sufficient for its ordinary use.

This has conventionally been established by carrying out a Waldram analysis to assess which parts of the room receive adequate direct natural light before and after the development. If more than 50% of the room is left with adequate light under that metric then, as a rough rule of thumb known as the ‘50/50 rule’, there would be no actionable infringement. It is widely accepted that the threshold is higher for residential properties, such that 55% of the room would generally need to be left with adequate light.

However, that methodology is not set in stone and is being strenuously challenged by many legal and surveying practitioners. Several recent high-profile cases have sought to persuade the courts to dispense with an assessment technique that was devised more than 100 years ago and instead consider more sophisticated modern methods of assessment that more accurately record how light may be affected within a building.

Unfortunately, these cases settled during trial and so practitioners and developers alike are none the wiser on the weight the courts would apply to those. The Waldram method therefore remains accepted practice for now, but watch this space.

What are the remedies?

The primary remedy for an actionable infringement of a right of light is an injunction preventing the carrying out of the offending works or even requiring their removal. However, the right to seek an injunction may be lost where there is a delay in bringing proceedings or where the conduct of the owner of the impacted building otherwise warrants it. In those circumstances the owner’s remedy would be limited to common law damages reflecting the loss in value of the impacted building, known as the book value.

Importantly, the court also has the discretion to award equitable damages instead of an injunction, which tend to be for a greater amount, reflecting what would have been paid to secure a release of the rights following a hypothetical negotiation.

This can be based on a multiple of the book value, but is normally equated to a share of the developer’s profit in the offending part of the development established using a cutback analysis, with the reported proportions awarded by the courts gravitating towards between 20% and 30% depending on what ‘feels right’.

There is no clear picture of how development risk should be taken into account in assessing that profit and there are added complexities where a number of owners have actionable claims, since the cutbacks for the impacted buildings will often be similar. To date, the courts have not opined on how any profit ‘pot’ should be shared in this situation and it remains a hotly contested point during negotiations to resolve right of light disputes.

It should be noted that an interim injunction preventing the carrying out – or requiring the cessation – of offending works can be sought by the owner of an impacted building pending a full trial.

The drawback is the owner may be required to give a cross undertaking in damages, where it agrees to pay (and potentially provide security for) any damages awarded to the developer if the court ultimately decides the injunction should not have been granted.

In any event, the owner’s negotiating position may be improved through allowing the works to reach a more advanced stage under the threat of a final injunction. For those reasons interim injunctions are rarely pursued in practice.

How will the court exercise its discretion?

The historic test for whether a court would award damages over an injunction was dependent on a number of criteria being met, but has in recent times been perceived to be overly restrictive.

There have since been moves away from that towards an approach that gives the court more discretion to achieve an outcome that has regard to the severity of the impact, the conduct of the parties and the proportionality of the respective remedies. The public benefit afforded by a development might also be judged a factor in some circumstances.

The lack of what might be termed a hard and fast rule means there can be considerable uncertainty around when a court will award damages over an injunction and what the measure of any damages will be. This inevitably leads to the question of how rights to light infringements can be avoided or managed in the context of a development – particularly within a city centre environment – which is something the second article will discuss.

Key terms

The Waldram analysis: This determines whether at least 0.2% of the dome of the sky is visible at table height in each sq ft of the room, which equates to one lumen – or approximately one candle’s worth – of light per sq ft.

Book value: This is usually calculated using an equivalent first zone measure under which the loss of light in each room is weighted by zone and the total then has a rent applied at a rate of pounds per sq ft, having regard to the location of the impacted building. That is then capitalised by reference to the yield of the impacted building.

This article was originally published in Estates Gazette on 8 January 2024, and was written in collaboration with Nick Lane, senior director at Point 2 Surveyors.