4 Nature of Permitted Development Under Class A
(a) Works for the erection, extension or alteration of a building
12.76 Section 336(1) of the 1990 Act defines a ‘building’ as including any structure or erection, and any part of a building, but not plant or machinery comprised in a building.
Class D.1 of Sch 2, Part 6 to the 2015 Order further provides that a ‘building’ does not include anything resulting from engineering operations. The precise attributes necessary before a structure or erection can be characterised as a ‘building’ are left undefined, and the courts will view it as a test of fact and degree whether a structure amounts to a ‘building’ or not.13012.77 The installation or modification of fixed equipment is thus not covered by Class A(a); but it may, depending on the facts, fall within the separate permission for engineering operations conferred by Class A(b) (below). Additionally, the erection of gates, fences and walls is regulated by Part 2 of the GDO, and not by Part 6. Note also that ‘significant alterations and extensions’ to a building are subject to restrictions in Class A.2(4) (below) and can only be carried out once. The reconstruction of an agricultural building can be a permitted development under this head – even if it involves the reconstruction of a building demolished by a previous enforcement notice.131 Furthermore, the fact that the user of the buildings – or their proposed user- is mixed does not preclude the application of GDO rights. The 2015 GDO does not preclude sites with mixed agricultural and non-agricultural usage from GDO rights. Indeed, as pointed out in South Oxon DC v East and Secretary of State132 there is usually an element of mixed user in most ‘agricultural’ enterprises – a factor that can only increase with greater farm diversification.
(b) Any excavation or engineering operations
12.78 Such operations are not subject to the additional restrictions (discussed below) that apply to building operations. This follows from the definition in Class D.1), viz that a ‘building’ does not include anything resulting from engineering operations. Class A.2(1)(b) provides that if the development involves either the extraction of minerals from the land (or any disused railway embankment on the land) or the removal of any mineral from any mineral/working deposit on the land, then the mineral shall not be moved off the land unless planning permission for the winning and working of the mineral concerned has been granted. Note also that Class A does not authorise the mining of minerals per se, even if they are to be used for agriculture on the holding and not moved off it. This is dealt with separately by Class C, discussed below, which gives limited permission for such activity.