Polmelin Tregidden St Martin Helston Cornwall TR12 6DS Data via plota.co.uk

Previously an area of outstanding natural beauty, which is still the designation in law. Since 2023 authorities must seek to further its purpose, not merely have regard to it.

Where development of farmland is needed, policy prefers poorer land over the best and most versatile (grades 1, 2 and 3a). Three sources: Natural England's post-1988 field surveys, which are definitive where they exist; the Defra predictive map for England (2025) and the Welsh Government predictive map, modelled from the soil map with 3a and 3b split; and the 1970s provisional map, which planners and other services still show, coarser and with grade 3 undivided. Where the provisional and predicted grades disagree, treat the predicted grade as the current estimate and expect an application to carry its own survey.

Nationally important archaeology protected by the Secretary of State. Work that affects the monument or its setting is rarely permitted.