The definition of 'DEVELOPMENT' for planning purposes not only refers to building, engineering and other operations, but includes the need for planning permission in circumstances where you wish to change the use of land or buildings.

A change in the use of land or buildings may arise by a simple alteration in the nature of the use, or through alterations and additions which modify the use. A change of use may also arise through a material intensification in the present use, or by subtly altering the present use to a point where the changes amount to development.

 Changes of use are not always a clear-cut issue and should be treated with care.

There are certain types of change of use, which do not require planning permission. For example, a change of use from one type of shop to another does not (normally) require planning permission. These are set out in the Town and Country Planning (Use Classes Order) 1987 [UCO].

Certain changes are permissible between and within the use classes without the need for planning permission, subject to satisfying the appropriate criteria.

Other uses are considered Sui Generis; that is, they are uses on their own unrelated to other uses. A change of use from say a field to a caravan park would require planning permission, so too a domestic garage to a business workshop, or house to an hotel etc.

You should first consider your permitted development rights then the Use Classes Order to determine whether your intended change of use requires planning permission or not. If in doubt consult the planning department or the e-service.

There may be circumstances where you only intend to make a minor alteration to the use of land or premises and this opens up the question of whether the change is so substantial as to require planning permission.

Any change of use must be a MATERIAL CHANGE OF USE in order to require consent. Defining what is and what is not a material change is often difficult and open to interpretation. Inevitably the courts have provided guidance over the years in deciding cases, but given the diversity of potential uses the issue remains open to debate.

Setting up a workbench in your domestic garage for private activities, hobbies, DIY etc is not a material change of use. However, if that workbench is used for commercial purposes - unrelated to the domestic use of the house - it is likely to be treated as a change of use for which planning permission would be required.

Additional or supplementary uses may also create a situation where planning permission is required. A builders yard used for the storage only of building materials, which then becomes used for the parking of vehicles may require planning permission, depending upon the circumstances of the case.

You should not overlook the limitations on use imposed by the planning permission over the land or buildings and any conditions that may be attached. The wording of planning permissions is often critical. For example, "use of land as a caravan park" is substantially different to, "use of land as a holiday caravan park". So too "use of building for B8 storage" from, "use of building for the storage of farm implements only".

 Essentially, any fundamental change of use from the present use to a completely different one (that is not allowed by the Use Classes Order or as permitted development) will require planning permission.

 A minor change of use may escape the need for planning permission because it is not considered so significant as to be a 'material' change. But care is required in assessing the significance of the change.

 The intensification of a use may also attract the need for planning permission if the enlarged use is so significant as to alter the original circumstances beyond what may be considered acceptable.

 Planning permissions should be checked to ensure that the proposal is not outside the terms of the consent or contrary to planning conditions.