I assume SPDs sink or swim with the Local Plan - Public forum - Planning Advisory Service (PAS)

The Act says that applications (and appeals) must be determined in accordance with the relevant policies of the development plan etc etc. The Act doesn't say that they must be determined in accordance with the advice in SPD's (although they might constitute "other material considerations"). If the policy is out-of-date then the SPD that hangs off it is likley to be out-of-date as well. However, the SPD might have something useful to say about the proposal which is relevant and if so, some weight should be given to it as a "material consideration". Has the SPD been the subject of full and proper public consultation and independent examination? If not, less weight will be given to it but I doubt if a decision-maker will ignore an SPD completely.

I think that most SPDs will require re-writing as they hark back to PPSs and RSS policies. Not only will the policy have to be NPPF compliant but so will the SPD. Some local authorities are publishing lists of which policies and SPDs will be carried forward into the new Local Plan. Arguments will have to be made as to the amount of 'weight' to be given to a SPD but it is currently easier to argue little weight than more in the present hiatus. Some lpas still seem surprised that the NPPF has come into effect.