The principle of sustainable development assumes that it is possible to predict the consequences of decisions taken in determining whether or not to allow a development to go ahead. Where there is any uncertainty, it is important that this is acknowledged and if 'unknown' or 'uncertain' consequences are potentially significant, that a precautionary approach is taken ie. nothing should be done that might prejudice or cause damage to resources elsewhere, unless there is clear and unequivocal justification.

Stepping back to take a strategic overview will allow future strategic and scheme specific problems to be reduced or avoided. At the very least, such problems can be anticipated and decisions made with knowledge of potential consequences.