My client worked from December 1999 to August 2007 while receiving IB. She stopped work because she was too ill to continue.

She has been rumbled and after a couple of CFIS interviews she was notified on 24 January that her IB has been disallowed from December 1999 including the period after she stopped work.

If she now makes a new claim for IB, does she have to make a case that her condition has deteriorated since an earlier date and if so what date?

Don't think she does, Peter. I think that requirement only applies if someone is kicked off IB on being found fit for work either under the PCA or the own occupation test, and makes a new claim on the basis of the same condition within six months of that finding. If they lose IB for other reasons - like actually going back to work without a finding of fit for work - I don't think they have to show recent deterioration, if they then need to reclaim. And I can't see that late notification of the return to work affects that...

See CPAG ch28 section 3

The deeming provision that someone is fit for work if they do work expressly applies notwithstanding that they have been to be incapable of work in accordance with the PCA. So there has not been any actual finding of fitness for work.

However you may very well find that the fact she has been working raises a query as to whether the original assessment was correct, so they will probably look for pretty strong evidence.

And she will almost certainly (gut feeling admittedly) have lost her linking provisions as her previous claim was not valid, so will no longer satisfy the contribution conditions for IB and have to claim IS in the alternative.