The Town and Country Planning (General Permitted Development) Order 1995

B.3    Development not permitted

Development is not permitted by Class B(b) if—

(a)the height of any additional plant or machinery within 3 kilometres of the perimeter of an aerodrome would exceed 3 metres;

(b)the height of any additional plant or machinery not within 3 kilometres of the perimeter of an aerodrome would exceed 12 metres;

(c)the height of any replacement plant or machinery would exceed that of the plant or machinery being replaced; or

(d)the area to be covered by the development would exceed 465 square metres calculated as described in paragraph D.2 below.