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

A.    Permitted development

The erection or construction and the maintenance, improvement or other alteration by a local authority or by an urban development corporation of—

(a) any small ancillary building, works or equipment on land belonging to or maintained by them required for the purposes of any function exercised by them on that land otherwise than as statutory undertakers;

(b) lamp standards, information kiosks, passenger shelters, public shelters and seats, telephone boxes, fire alarms, public drinking fountains, horse troughs, refuse bins or baskets, barriers for the control of people waiting to enter public service vehicles, and similar structures or works required in connection with the operation of any public service administered by them.