The Island Development Plan ("IDP") is a document which contains the factors and policies to be taken in to account by the Development and Planning Authority ("DPA") when making decisions on applications for planning permission. It was prepared by the DPA and was subject to various stages of consultation and public engagement as well as a planning inquiry, carried out by independent planning inspectors, before it was adopted by the States in November 2016.

Generally speaking, applications for planning permission must comply with the policies within the IDP for planning permission to be granted.

The document sets out the planning policies for the whole of the island and provides for the development Guernsey needs to maintain to ensure economic prosperity and to provide for social and environmental needs, whilst ensuring the island remains an attractive place to live, work and visit.

The IDP covers issues such as: how the local economy will be supported through the use of land; where new homes may be built; and where industry, leisure and retail facilities may be located. It provides for development to be focused within and around the two main centres of Town and the Bridge (where the majority of development will be) and the local centres of St Martin, Cobo, St Pierre du Bois, L'Islet, Forest, Forest West and L'Aumone.

The IDP has a lifespan of 10 years, but to ensure it is effective and relevant, it is monitored by the DPA to ascertain whether policies need to be amended or updated to adapt to changing circumstances. For example, if the States decide that the visitor accommodation stock no longer needs to be maintained at the current level, it may decide to amend the relevant policies to make it easier for visitor accommodation to be changed to another use. However, making amendments to the IDP is not a simple process. Any proposed amendments would be subject to the full inquiry procedure including the necessary consultations and a planning inquiry carried out by independent planning inspectors. The inquiry would be followed by formal reporting prior to consideration and adoption by the States.