It is clear that, yet again, I have to steer a careful course between Scylla and Charybdis—I refer to the hon. Members for Vale of York (Miss McIntosh) and for Guildford (Sue Doughty). Between them, they ask me to do more and less. Both requests are, as I hope to persuade the Committee, based on misapprehensions. The exceptions in clause 102(4) refer specifically to areas where safety is a paramount priority for transport, and where movement and safety are at a premium. The two other examples in the list are lighthouses and prisons, and I am sure that the safety considerations necessary for them are obvious to all. We do not want the Bill to be used in such circumstances; the Bill has a very clear focus on local circumstances. The hon. Member for Guildford referred to existing legislation. I will come to that in a moment, because there is a need to consider the interface between the proposals before us and the existing legislation. It may be helpful if I start by setting out the scope of this measure—what it does and does not do.
The clause does not provide local authorities with new general powers to control artificial lighting. Rather, local authorities will be given the ability to treat as a statutory nuisance particular instances of artificial lighting that qualify as a common law nuisance or are prejudicial to health. These terms have been used for many years, and there is extensive case law on their meaning. The need to achieve a reasonable balance between the interests of individuals who are adversely affected by an activity and the need to carry on that activity is integral to the law on statutory nuisance. For artificial lighting, local authorities will need to balance the nuisance caused by particular lights against the need for adequate lighting on, for example, security or safety grounds.
The law on statutory nuisance also contains a specific defence of having used ''best practical means''—I shall refer back to those three words—to prevent or suppress the effects of certain statutory nuisances, particularly those arising on trade, business and industrial premises. Clause 103 deals with the availability of this defence for both artificial lighting and nuisance insects. This provision, in effect, permits an activity that might be otherwise be unreasonable to continue where those who are responsible for it have used the best means available to them to prevent it, or to reduce its impact.