One of the important provisions of the directive is that the IM senior official identify information resources of business value based on analysis of departmental functions and activities carried out by the department and to enable it to support its legislated mandate, the protection of information resources of business value. So within the context of the operation of any department, they have to make those decisions and apply this policy. So it would be the senior IM official in the department who would be responsible for making that call.
On November 24th, 2009. See this statement in context.