Most planning departments have an adequate number of staff to police the measure.
The cost may be high initially because of the backlog of cases, but it will probably drop. Gentleman is partly right, but the view that the number of cases will fall may be wrong. Even if, as he suggests, planning officers already go out to advise people, they will have more work when they also have to make a judgment, and perhaps carry out an enforcement procedure. It is unrealistic to expect the Bill not to create more work for them. Planning officers make a judgment now.