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

A.1    Development not permitted

Development is not permitted by Class A if—

(a)the building as extended or altered is to be used for purposes other than those of the undertaking concerned;

(b)the building is to be used for a purpose other than—

(i)in the case of an industrial building, the carrying out of an industrial process or the provision of employee facilities;

(ii)in the case of a warehouse, storage or distribution or the provision of employee facilities;

(c)the height of the building as extended or altered would exceed the height of the original building;

(d)the cubic content of the original building would be exceeded by more than—

(i)10%, in respect of development on any article 1(5) land, or

(ii)25%, in any other case;

(e)the floor space of the original building would be exceeded by more than—

(i)500 square metres in respect of development on any article 1(5) land, or

(ii)1,000 square metres in any other case;

(f)the external appearance of the premises of the undertaking concerned would be materially affected;

(g)any part of the development would be carried out within 5 metres of any boundary of the curtilage of the premises; or

(h)the development would lead to a reduction in the space available for the parking or turning of vehicles.