When is it required?
In all cases.
What is required?
All applications must include copies of a location plan based on an up-to-date map. This should be at a scale of 1:1,250 (or 1:2,500 for remote sites). The application site should be edged clearly with a red line. It should include all land necessary to carry out the proposed development, for example, land required for access to the site from a public highway, visibility splays, landscaping, car parking and open areas around buildings. A blue line should be drawn around any other land owned by the applicant, close to or adjoining the application site.
Plans should identify sufficient roads and/or buildings on land adjoining the application site to ensure that the exact location of the application site is clear.
Ordnance and Survey based location plans can be obtained from internet suppliers. The Planning Portal also recommends sites for purchasing maps.