5 Limitations on Permitted Development

(a) Limitation by type

12.79 Class A.1 contains restrictions preventing the erection of dwelling houses or other buildings not designed for agricultural use. The following types of development are expressly not permitted under the 2015 Order:

•A development which would consist of or include the erection, extension or alteration of a dwelling.

•A development which would involve the provision of a building, structure or works not designed for agricultural purposes. Whether development of a building, structure or works is or is not designed for the purposes of agriculture falls to be decided by its physical appearance and layout (Harding v Secretary of State for the Environment).¹³³ An aircraft hangar, for instance, is not a building ‘designed’ for the purposes of agriculture (see Belmont Farms Ltd v Minister of Housing and Local Government).¹³⁴

(b) Limitation by size/ground area

12.80 Development is not permitted if the ground area to be covered by any works, structure or building would exceed 465 square metres. This limitation applies to two types of development otherwise allowed by Part 6:

•any works or structure (other than a fence) for the purposes of accommodating livestock, or any plant or machinery arising from engineering operations; and

•any building erected, or any building altered or extended, by virtue of Class A.

12.81 A structure will only be characterised as a ‘fence’, and thus not caught by the area restriction, if its purpose is to enclose. A windbreak, although structurally similar, is therefore not a ‘fence’ and will ( if it constitutes a ‘building’ ) be subject to the 465 sq.

12.82 For these purposes the relevant ground area is the ground area which would be covered by the proposed development, together with the ground area of any building (other than a dwelling), or any structure, works, plant or machinery within the same unit which is being provided, or has been provided within the preceding two years and any part of which would be within 90 metres of the proposed development (Class D.1(2) (italics added)). If the development, thus measures, would exceed 465 sq metres in area then planning permission is required. This restriction, however, requires all buildings within 90 metres of the proposed development that have been erected in the preceding two years to be added to the ground area calculation. The intent is to prevent intensive development of small areas of land. Note, however, that if a building is to be placed within 90 metres of a building previously built within the last two years, planning permission may be required; alternatively it may be necessary to await the expiry of the two-year period before building. There is no control of buildings with an area of less than 465 sq metres, however, provided they are spaced so that none impinges on a radius of 90 metres around any other. If this happens the ground area of the two must be aggregated, and if this exceeds 465 sq. metres either planning permission will be needed, or there must be a delay until the two-year period has elapsed.

(c) Height near aerodromes

12.83 Development is not permitted if the height of any part of the building, structure or works concerned that is within 3 kilometres of the perimeter of an aerodrome would exceed 3 metres. This would, for instance, prevent the erection without planning permission of silos exceeding 3 metres in height near the perimeter of an airfield. The restriction on permitted development is relaxed for development outside the 3-kilometre radius of an aerodrome. In such cases development is not permitted if any part of the proposed building, structure or works would exceed 12 metres in height (Class A.1(g)).

(d) Proximity to metalled roads

12.84 If any part of a proposed development is within 25 metres of the metalled portion of a trunk or classified road then the whole development is unauthorised – and not just the portion within the 25-metre radius.¹³⁶ This restriction does not apply to unclassified roads.

12.85 The carrying out of works to construct, lay out or form a means of access to a permitted development is allowed by Part 2, Class B (Minor Operations) of the GDO, but only if the road to which access is sought is unclassified. The construction of the access must, moreover, be required in connection with development permitted by the GDO eg by Part 6 in the case of agriculture. If, however, access is sought to a classified or trunk road, then Class 6 rights do not include building or materially widening an access road.¹³⁷

(e) Engineering operations: fish farming

12.86 Engineering operations or excavations on or over Art 2(4) land which are connected with fish farming are not permitted by Class A (Class A.1(j)).

(f) Control of siting of livestock units, slurry and sludge storage

12.87 Under Class A(1)(i), development is not permitted if it would consist of, or include, the erection or construction of, or the carrying out of any works to, a building, structure or excavation used or to be used for the accommodation of livestock, or for the storage of slurry or sewage sludge, if the building, structure etc. is, or would be, within 400 metres of the curtilage of any protected building. This control on the siting of livestock and slurry units is introduced to minimise the nuisance to residential occupiers caused by insensitive siting of such facilities. By virtue of Class D.1 ‘protected buildings’ include any permanent building that is normally occupied by people, or would be so occupied if used for the purposes for which it is apt. But it does not include a building within the agricultural unit itself or an agricultural building on an adjacent unit. The control will, however, apply to protect residential buildings on an adjacent unit.