Mr. Gavin Lawlor:

This comes back to implementation. People might get planning permission for their land but if it turns out that part of those lands are actually owned by a third party then the permission cannot be implemented. This is tough luck on the applicant, unfortunately, but that is the way it works. Responsibility sits with the applicants to ensure the plans and particulars they have lodged are accurate and they do, in fact, own the property. If they do not, they will suffer the burden of not benefiting from the planning permission.