A fully updated 4th edition of the definitive work on permitted changes of use. The extensive changes to the Use Classes Order in 2020 were clearly going to be followed by consequential amendments to the GPDO, especially to permitted development rights for changes of use in Parts 3 and 4 of its Second Schedule. This has led to the most radical shake-up of these provisions since permitted development rights for changes of use began to be significantly expanded from 2013 onwards. The new provisions came into force on 1 August 2021, and the Fourth Edition of A Practical Guide to Permitted Changes of Use contains a fully updated text explaining these legislative changes in detail. Some significant expansion of PD rights has been brought about, notably Class MA, which permits the residential conversion of the wide range of buildings in commercial, business or service uses that now fall within Use Class E. Some former PD rights have now been removed. A few of these were simply redundant, as a result of both the pre-existing use and the new use now falling within one and the same Use Class, so that a change of use from one to the other is no longer development at all. Others have been replaced by new or enlarged PD rights under other Classes. For example, the revised and expanded Class A now embraces previous PD rights under Classes A, B, C, D, E and F (to the extent that some of these have not been rendered altogether redundant). This has left a number of PD rights that have been removed from the GPDO altogether without being replaced in any way. These are defined as 'protected development', and their life has been extended for a limited period. All these former PD rights are identified in the book, and the transitional rules that apply to them are explained in detail. This Fourth Edition of A Practical Guide to Permitted Changes of Use will be an essential resource for property owners, developers and their professional advisers, giving them a completely up-to-date guide to this increasingly complicated and much-amended legislation.