# The Town and Country Planning (General Permitted Development) (Scotland) Order 1992, Paragraph 18

Extent: S

(1) The carrying out on agricultural land comprised in an agricultural unit of—
(a) works for the erection, extension or alteration of a building;
(b) the formation, alteration or maintenance of private ways; or
(c) any excavation or engineering operations,
requisite for the purposes of agriculture within that unit.
(1A) Development is not permitted by this class if, in the case of any development referred to in sub-paragraph (1)(a), the land is within a historic battlefield;
(2) Subject to paragraph (4) development is not permitted by this class if—
(a) the development would be carried out on agricultural land less than 0.4 hectare in area;
(b) it would consist of or include the erection, extension or alteration of a dwelling;
(c) a building, structure or works not designed for the purposes of agriculture would be provided on the land;
(d) the ground area to be covered by any works or structure (other than a fence) for the purposes of accommodating livestock or any plant or machinery arising from engineering operations would exceed 465 square metres, calculated as described in sub-paragraph (5),
(da) the ground area to be covered by any building erected or any building as extended or altered by virtue of this class—
(i) is situated in a designated area and would exceed 465 square metres, calculated as described in sub-paragraph (5), or
(ii) is situated elsewhere and would exceed 1,000 square metres, calculated as described in sub-paragraph (5),
(e) the height of any part of the building, structure or works within 3 kilometres of the perimeter of an aerodrome would exceed 3 metres;
(f) the height of any part of the building, structure or works outwith 3 kilometres of the perimeter of an aerodrome would exceed 12 metres;
(g) any part of the development would be within 25 metres of the metalled portion of a trunk or classified road; or
(h) it would consist of or include the erection or construction of, or the carrying out of any works to, a building, structure or erection used or to be used for housing pigs, poultry, rabbits or animals bred for their skin or fur or for the storage of slurry or sewage sludge, and the building, structure or works is or would be within 400 metres of the curtilage of any protected building.
(3) Development is permitted by this class subject to the following conditions—
(a) where development is carried out within 400 metres of the curtilage of a protected building, any building, structure, erection or works resulting from the development shall not be used for housing pigs, poultry, rabbits or animals bred for their skin or fur or for the storage of slurry or sewage sludge;
(b) where the development involves—
(i) the extraction of any mineral from the land or from any disused railway embankment on the land; or
(ii) the removal of any mineral from a mineral-working deposit on the land,
the mineral shall not be moved off the land, unless planning permission for the winning and working of that mineral has been granted on an application made under Part III of the Act;
(c) in the case of development which involves the deposit of waste materials on or under the land, no waste materials shall be brought onto the land from elsewhere except for development of the kind described in sub-paragraph (1)(a) or the creation of a hard surface, where the materials are incorporated into the building or works forthwith.
(4) (a) Development consisting of the erection of a building or the significant extension or significant alteration of a building ... is permitted by this class subject to the following conditions:—
(i) the developer shall, before beginning the development, apply to the planning authority for a determination as to whether the prior approval of the authority will be required to the siting, design and external appearance of the building;
(ii) the application shall be accompanied by a written description of the proposed develop ment, the materials to be used and a plan indicating the site together with any fee required to be paid;
(iii) the development shall not be begun before the occurrence of one of the following:—
(aa) the receipt by the applicant from the planning authority of a written notice of their determination that such prior approval is not required;
(bb) where the planning authority gives the applicant notice within 28 days following the date of receiving his application of their determination that such prior approval is required, the giving of such approval;
(cc) the expiry of 28 days following the date on which the application was received by the planning authority without the planning authority making any determination as to whether such approval is required or notifying the applicant of their determination;
(iv) the development shall, except to the extent that the planning authority otherwise agree in writing, be carried out—
(aa) where prior approval is required, in accordance with the details approved;
(bb) where prior approval is not required, in accordance with the details submitted with the application;
(v) the development shall be carried out—
(aa) where approval has been given by the planning authority, within a period of five years from the date on which approval was given;
(bb) in any other case, within a period of five years from the date on which the planning authority were given the information referred to in sub-paragraph (a)(ii);
(b) development consisting of the significant extension or the significant alteration of a building, may be carried out only once in respect of that building.
(4A) Development consisting of the formation or alteration of a private way is permitted by this class subject to the following conditions—
(a) the developer must before beginning the development apply to the planning authority for a determination as to whether the prior approval of the authority is required in respect of the design, manner of construction or route of the private way;
(b) the application is to be accompanied by—
(i) a description of the proposed development, including the proposed design and manner of construction, details of the materials to be used and a plan indicating the route of the private way; and
(ii) any fee required to be paid;
(c) the development is not to be commenced before the occurrence of one of the following:—
(i) the receipt by the applicant from the planning authority of a written notice of their determination that their prior approval is not required;
(ii) the expiry of a period of 28 days following the date on which the application was received by the planning authority without the planning authority giving notice to the applicant of their determination that, or the extent to which, such approval is required; or
(iii) the applicant has (or to the extent required has) received such approval from the planning authority;
(d) the development must, except to the extent that the planning authority otherwise agree in writing, be carried out—
(i) to the extent to which prior approval is required, in accordance with the details approved;
(ii) to the extent to which prior approval is not required, in accordance with the details submitted with the application; and
(e) the development is to be carried out within a period of 3 years from the date on which all approvals required in accordance with this paragraph have been given.
(5) For the purposes of this class—
(a) the area of 0.4 hectares shall comprise one piece of land except within the areas of the following planning authorities, namely Argyll and Bute District Council, Badenoch and Strathspey District Council, Caithness District Council, Inverness District Council, Lochaber District Council, Orkney Islands Council, Ross and Cromarty District Council, Shetland Islands Council, Skye and Lochalsh District Council, Sutherland District Council and Western Isles Islands Council, where the area of 0.4 hectares may be calculated by adding together the areas of separate parcels of land;
(b) the ground area referred to in sub-paragraph (2)(d) is the sum of—
(i) the ground area which would be covered by the proposed development; and
(ii) 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;
(c) the 400 metres measurement referred to in sub-paragraphs (2) and (3) is to be measured along the ground;
(d) “protected building” means any permanent building which is normally occupied by people or would be so occupied, if it were in use for purposes for which it is apt; but does not include—
(i) a building within the agricultural unit;
(ii) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
(iii) a dwelling or other building on another agricultural unit which is used for or in connection with agriculture.

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Source: https://www.legislation.gov.uk/uksi/1992/223/schedule/1/class/18 (the official version)
Page: https://openlegislation.uk/town-and-country-planning-general-permitted-development-scotland-order-1992/schedule-1/class/18
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.