Rights of light give protection to light coming through an aperture, like a window, to a room. If the light to that room is diminished by a new development nearby to such an extent that it is a nuisance then this can lead to court action.
Until recently it had been thought that if a building owner had not taken prompt action to protect their rights of light and a neighbouring development had been completed, then a court would award damages rather than an injunction. An injunction would require some or all of the new development to be demolished and is, therefore, a drastic solution.
The case of HKRUK II (CHC) Ltd v Heaney  caused concern amongst developers as it established that it was possible to obtain an injunction even if the new building had been completed. A 2014 case, Coventry and others v Lawrence, suggested that the courts should take a more flexible approach and not award an injunction too readily.
The recent case of Beaumont Business Centres Ltd v Florala Properties Ltd  now causes concern. Florala owned a building in London and extended it upwards to create an aparthotel. The extension works interfered with the light to the neighbouring office block. Despite the work being completed in 2018, the court declared that Beaumont would be entitled to an injunction, requiring Floral to cut back its development. They had gone ahead knowing of the risk it was taking and had acted in an unneighbourly fashion.
If a risk is identified then discussions should take place with the neighbouring owners to reach an amicable settlement; either a compensation payment or a re-design of the new building. This should be properly and promptly documented to prevent disputes at a later date.