In Ardagh Glass v Chester City Council (2009) a local planning authority was scolded for betraying its responsibilities by not taking enforcement action when faced with a large glass manufacturing plant, which had no valid planning permission, being operated for approaching four years. It is now clear however, that the case does not mean "open season" on all refusals by planning authorities to take enforcement action.

In the recent R (oao Baker) v Bath and East Somerset Council and Hinton Organics Limited (2009) a planning permission which temporarily allowed a field to be used as a waste composting site was expiring. Litigation over lack of environmental impact assessment delayed the developer's application for a replacement permission. The claimant sought an order from the court requiring the planning authority to take enforcement action to stop the then unlawful user but this time the court held that the delays that had occurred were understandable. In the circumstances, the planning authority had lawfully exercised its discretion not to take enforcement action.

The difference between Ardagh and Hinton appears to be urgency. In Ardagh, it was clear that unless the planning authority acted quickly, a major development would be immune from enforcement due to the passage of time. In Hinton, the operation was being carried on after cessation of temporary planning permission but here was no suggestion that this would gain immunity any time soon. The message seems to be that courts are only likely to get involved if there is an imminent threat of unlawful development obtaining immunity unless the planning authority acts.