In Britain, planning permission is official permission that you must get from the local authority before building something new or adding something to an existing building.
planning permission in British English
noun
(in Britain) formal permission that must be obtained from a local authority before development or a change of use of land or buildings
Examples of 'planning permission' in a sentence
planning permission
The only difficulty appeared to be a problem involving stables which had been built and for which no planning permission had been given.
Cathy Kelly JUST BETWEEN US (2002)
It must have been before Forest Havens got planning permission, or around that time anyway.
Stuart Harrison LOST SUMMER (2002)
I understand that prior to planning permission approval being granted you were opposed to it?