Development projects receive the greatest scrutiny at the planning application stage. The policies set out in various planning documents help to inform the acceptability of each planning application.
In terms of wildlife protection, these policies typically build on the protection set out in the legislation, provide guidance on the interpretation of the legal duties of the planning authority or provide protection for features of local biodiversity importance. In England, Wales, Scotland and Northern Ireland, such policies should also reflect the legal duty that local authorities have to the conservation of biodiversity.
The setting of planning policy is undertaken separately by the devolved administrations of the UK and then again at more local levels. In England, Wales and Scotland there are typically two tiers of policy (the national and the local).
In the past, three tiers of policy were more common, with a middle tier at the county or regional level. The middle tier has all but gone, although it may be about to make a reappearance in Wales. In Northern Ireland and Ireland, there are three tiers of planning policy.
In addition to the actual policies, various organisations have produced guidelines on how biodiversity should be treated in the planning process. These guidelines have varying levels of weight and geographical application. The following sections summarise the planning policy and guidance which is applicable in Britain and Ireland.