is it development or isn’t it? 

Is it development or not – that is a common question here at Planning Geek!

You may be visiting the site due to our comprehensive coverage of the General Permitted Development Order (GPDO) but before you dive into that we need to work out what is development. Do you really need permission to carry out those works? If it is development, yes you do – if it isn’t, no you don’t!


Development is defined by those elements set out in section 55 of the Town & Country Planning Act 1990. This includes:

  • building operations (e.g. structural alterations, construction, rebuilding, most demolition);
  • material changes of use of land and buildings;
  • subdivision of a building (including any part it) used as a dwellinghouse for use as two or more separate dwellinghouses
  • These all require planning permission


Do you need permission?



Not Development


The categories of work that do not amount to ‘development’ are set out in section 55(2) of the Town and Country Planning Act 1990. As a general rule, this also applies to flats as well as houses. These include, but are not limited to, the following:

  • interior alterations (except mezzanine floors which increase the floorspace of retail premises by more than 200 square metres);
  • building operations which do not materially affect the external appearance of a building. The term ‘materially affect’ has no statutory definition, but is linked to the significance of the change which is made to a building’s external appearance;
  • a change in the primary use of land or buildings, where the before and after use falls within the same use class. For example changing from a post office to a hairdressers as these both fall under use class E.
  • These are not development and do not require planning or legislation allows it to go ahead


Planning Permission required? 


If the work planned is development and therefore requires planning permission this can be obtained in a few ways, including submitting an application to the planning department of the local authority (LPA) or by means of the general permitted development order or GPDO for short. The GPDO is your planning permission! You just need to meet the criteria laid down in it. This was last fully revised in 2015 but there have been a few amendments since then annually and the latest in 2020. It is important not to rely solely upon the 2015 version as there have been several changes. We will aim to keep all articles on this website up to date. All the official variations to the GPDO can be found on our Links page, but 99% of these are updated on the relevant pages at Planning Geek.


Page Updated: 7th March 2023