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

C.    Permitted development

The carrying out on operational land outside but within 8 kilometres of the perimeter of a relevant airport, by a relevant airport operator or its agent, of development in connection with—

(a)the provision of air traffic control services,

(b)the navigation of aircraft using the airport, or

(c)the monitoring of the movement of aircraft using the airport.