The Town and Country Planning (General Permitted Development) (England) Order 2015 No. 596

SCHEDULE 2 Permitted development rights

PART 19 Development by the Crown or for national security purposes

Class I – emergency use of land by the Crown connected with air traffic services

Permitted development

I  The use of land by or on behalf of the Crown in an emergency to station moveable apparatus replacing unserviceable apparatus in connection with the provision of air traffic services.