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

B.    Permitted development

The carrying out on agricultural land comprised in an agricultural unit of not less than 0.4 but less than 5 hectares in area of development consisting of—

(a)the extension or alteration of an agricultural building;

(b)the installation of additional or replacement plant or machinery;

(c)the provision, rearrangement or replacement of a sewer, main, pipe, cable or other apparatus;

(d)the provision, rearrangement or replacement of a private way;

(e)the provision of a hard surface;

(f)the deposit of waste; or

(g)the carrying out of any of the following operations in connection with fish farming, namely, repairing ponds and raceways; the installation of grading machinery, aeration equipment or flow meters and any associated channel; the dredging of ponds; and the replacement of tanks and nets,

where the development is reasonably necessary for the purposes of agriculture within the unit.