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 T – electronic communication apparatus etc for national security purposes

Development not permitted

T.2  Development consisting of the installation of apparatus is not permitted by Class T(a) on article 2(3) land unless—

(a) the land on which the apparatus is to be installed is, or forms part of, a site on which there is existing electronic communication apparatus;

(b) the existing apparatus was installed on the site on or before the relevant day; and

(c) the site was Crown land on the relevant day.