Summary of the latest Permitted Development changes - May 30th 2013. 

Extensions to Buildings in Class A Use [Part 42, Class A]

This temporary increase in PD rights only applies to Class A1 & A2 uses, even though Class 42 as a whole applies to all A-Class uses.

The floorspace limit for additions to the original building is increased to 100m² or 50%, whichever is the lesser [previously it was 50m² or 25%], unless the premises are in a SSSI.

The current restriction on extensions not being within 2m of a boundary is lifted for the temporary period, subject to it not being next to a C-Class [residential] use, within a SSSI or on Article 1(5) land.

Again, the developer must give the LPA notice of the completion of the extension works, providing details of the date of completion, and a description of the building works, including its location and dimensions.