The potential problems with the 5 year land supply were all highlighted in July 2009 in the report of a Task and Finish Forum on 5 year land supply (here are extracts):

1. Our assessment of our District wide figures shows that we have only just over five years availability. An Inspector at a planning application appeal could take the view that this is close enough to the five year threshold to side with an applicant/dismiss our arguments.
2. The District wide five year figure is based on our assessment and assumptions we have made. A developer might challenge these and come to a different conclusion (i.e. that land supply falls under five years) and persuade an Inspector that his/her evaluation is the more accurate.
3. Circumstances change and assessment/s done at the present time (and initially in 2008) can and will be out of date in the future.

Unfortunately, the document has since been removed from the EDDC website.