Brocket Park Brocket Hall Marford Road Lemsford Welwyn Garden City AL8 7XG Data via plota.co.uk

Green belt policy allows a short list of exceptions, such as limited extensions and replacement buildings. Anything else needs very special circumstances that clearly outweigh the harm.

The Environment Agency flood map for planning. Homes in zone 3 must also pass the sequential test. Surface water flooding is a separate map.

Registered parks and gardens, battlefields, world heritage sites and protected wrecks are designated heritage assets: harm needs clear and convincing justification.

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.