To what extent will minor modifications be allowed to a planning permission? In practice, minor modifications will be recorded in correspondence between the developer and the LA, with revised plans being deposited.

The classic test for deciding what modifications can be made to an existing planning permission was laid down in Wheatcroft [1980] : ‘the result must not be substantially different from the development applied for’. It is for the LPA to exercise reasonable judgment ‘as to whether there is a significant difference or not’.

The real question is the extent to which there is potential for a planning permission to be ‘stretched’, especially where outline planning permission exists for development described in the application documents for a certain size (eg by reference to floor space or number of dwellings). It may be possible to obtain reserved matters approval which exceeds such limits if the change is not ‘significant’ or ‘substantial’. Sometimes, the LA can be persuaded to refer to the quantum of the development (eg proposed floor space or housing unit numbers) as ‘approximate’ so as to allow room for manoeuvre in the future. Provided that the parameters of the proposed development comply with the General Development Procedure Order requirements to set out ‘the approximate location of buildings, routes and open spaces’ and ‘the upper and lower limit for the height, width and length of each building stated in the planning application’ there should not be any particular difficulty in describing quantum of development in approximate terms, especially for larger applications where inevitably reserved matters approvals will fix precise amounts of floor space and housing numbers. As always, however, any significant or substantial deviation runs the risk of falling foul of the Wheatcroft test. Source: Pinsent Masons .© Practical Lawyer