[holding answer 17 December 2007]: Planning Policy Statement 3—Housing requires local authorities to set targets in local plans for the amount of affordable housing to be delivered in their area, and to set out the range of circumstances in which contributing towards affordable housing will be sought.
It is for local planning authorities to decide, under the Use Classes Order, whether the use of a particular premises is sui generis, and whether it is appropriate to seek affordable housing contributions from proposed new developments which they deem to be sui generis.