Incorrect LPA advice on the need for planning permission - Public forum - Planning Advisory Service (PAS)

An LPA advises that planning permission is not required and a development takes place, with Listed Building consent. But, following a complaint by a third party, the LPA  decides that PP should have been required. Can this requirement be applied retrospectively? If so, who is liable for the cost of the application, and for any subsequent works should the PP require changes to the development?