The Hadley Homes, Kimberley Industrial Estate Walthamstow appeal decision (May 2011) makes essential reading for any applicant/appellant preparing a s 106 (agreement or unilateral) where not all of the site is in hand. In the Walthamstow case, part of the site was owned by the Council itself and fell outside the 106 with no agreement as to how it would be brought into the development. This, combined with the way the 106 was worded (in the view of the Secretary of State, "purport(s) to make provisions relating to the whole of the site but .(without any) mechanism for applying them to the excluded land") led to the conclusion that the 106 was sufficiently flawed so that it could not be relied on and the appeal should fail.
It will often be the case that an applicant does not control all of the land within the application site and it is not the case that a 106 must bind the entirety of the application site. However, care must be taken to ensure that the 106 package is deliverable in those circumstances, and that the owner of the land outside of the 106 cannot implement the permission and avoid obligations.