called for interview at job centre

Thank you. I appreciate the distinction, and that is certainly a concern. You'll appreciate I am now fairly worried!

The trouble is that I don't specifically recall a point where I was asked to notify DWP of any other income. You'll appreciate of course that over a claim of many years duration, my memory isn't 100%.
When the claim started it was Invalidity benefit and I was still getting a salary from my employers. I suppose there must have been questions at the start of the claim about any other income, but at the start of the claim, I wasn't getting PHI.

HMRC have always been aware of the PHI as I pay tax on it.

If I was ever asked about other income, I certainly would have informed DWP.

After some searching, I have found copies of all my Incapacity for work forms (IB50s) going back to 1999 and there aren't any questions on them about other income.

I vaguely remember getting an information booklet(s) with routine letters about my claim, and I have a vague memory of reading that occupational pensions/PHI could affect claims started after a certain date, and you had to tell DWP about them, but that this didn't apply to existing claims. Unfortunately I can't find any of these booklets and suspect that I chucked them out a few years ago when I decided that keeping all the paperwork from all my claims was too much.

Any comments to help with my now mounting anxiety would be very welcome!

Apologies if this is a repeat of a message sent this afternoon, but I'm not sure if the system accepted that one.

Thank you for the information and I understand the distinction between actually disregarding the PHI and not deducting for it.

My concern is that I don't recall telling the DWP about the PHI. There was no intention to deceive and I don't think there would have been any advantage in not telling them at that point, as PHI didn't affect your Incapacity benefit.
At the point of the original claim I was still in employment, on sick leave, and I continued to be employed for some years. When I was dismissed and the PHI kicked in I'm not sure I was aware that this was notifiable.

Would I have been asked about other income at any point e.g. during re-assessments of my Incapacity benefit?
I vaguely remember mentioning the PHI on forms but don't remember when or what these were for.
HMRC have always been aware of the PHI as it is taxable.

Thank you very much Gordon, that is reassuring. I have fairly full documentation of the PHI - it was a group policy taken out by the employers; I was paid directly by the insurers after dismissal from my job for ill-health.

Am I looking for the start date of the PHI payments, and/or is there anything else to look for?