Light pollution is probably best described as artificial light that is allowed to illuminate or pollute areas not intended to be lit.

Intrusive light is the intrusion of over bright or poorly directed lights onto neighbouring property, which affect the neighbours' right to enjoy their own property. A typical example would be an inconsiderately directed security light shining into a bedroom window.

England & Wales

Preventing light pollution

Before going to the expense and effort of installing lighting, a few simple questions should be asked:

• Is lighting necessary?
• Could safety or security be achieved by other measures, such as segregation or screening of an area?
• Do the lights have to be on all night, for example, over advertising hoardings, the exterior of buildings or empty car parks?
• If lighting is the best option, then only the right amount of light for the task should be installed. Lighting will then only become a problem if it is poorly designed or incorrectly installed.

If lighting is necessary, a number of measures can be taken to avoid causing a nuisance:

• For domestic security lights, a 150W lamp is adequate. High power (300/500W) lamps create too much glare, thus reducing security. For an all-night porch light, a 9W lamp is more than adequate in most situations.
• Make sure that lights are correctly adjusted, so that they only illuminate the surface intended, and do not throw light onto neighbouring property.
• Security lights should be correctly adjusted, so that they only pick up the movement of persons in the area intended and not beyond.
• To reduce the effects of glare, main beam angles of all lights should be below 70 degrees.
• Make sure security lights are correctly adjusted, so that they only pick up the movement of persons in the area intended and not beyond direct light downwards. If uplighting has to be used, then install shields or baffles above the lamp to reduce the amount of wasted upward light.
• Do not install equipment which spreads light above the horizontal.

Dealing with light pollution

The best method of dealing with light pollution is at the planning stage. This is an ideal time to influence the design or installation of lighting schemes. However, not all developments require planning consent, in particular, premises used for transport purposes, and other premises where high levels of light are required for safety and security reasons. Generally, developments involving the carrying out of building or engineering, or which involve making material changes to existing buildings or land, will require planning consent.

Local authorities receiving complaints about light in England and Wales, can now assess whether the light is a statutory nuisance under the Clean Neighbourhoods and Environment Act 2005. This extends the nuisance provisions of the Environmental Protection Act 1990, to cover artificial light emitted from premises (excluding transport facilities, freight depots, lighthouses, defence premises and prisons).

Statutory nuisance

Civil action can be taken by an individual to tackle a lighting problem. They would have to be able to prove that a nuisance exists. The statutory nuisance dealing with light is defined as "artificial light emitted from premises so as to be prejudicial to health or a nuisance". Nuisance, in this context, is anything that would be regarded as an unreasonable interference with someone's use of their property, or prejudicial to their, or someone else's, health.

The statutory nuisance regime will not be available in certain instances, in particular, in relation to premises used for transport purposes, and other premises where high levels of light are required for safety and security reasons.

Statutory nuisance in terms of the Environmental Protection Act is dealt with in more detail in our Pollution section.

Northern Ireland

There is currently no legislation in Northern Ireland in relation to lighting, though legislation in relation to noise and statutory nuisances is planned, but is currently still in the early consultation stages. If you have a problem with lighting, you should contact your local council who may be able to assist you.