David then joined the Planning Directorate of the Department of the Environment where he was involved in giving advice on land use planning and mineral workings in England, later heading the Land Stability Branch, with responsibility for initiating and managing research on land stability issues and the planning policy lead for land stability, the environmental effects of mineral working, pollution control flooding and the coast. After retirement, he acted as a consultant for a few years, advising the Irish and Isle of Man Governments on their planning policy on flooding.