Can I tell employer about disability without

[runescape]

officially/formally disclosing (i.e., not telling HR, and not having it on my record) I do not need any reasonable adjustments

I was thinking of mentioning it informally in passing to my Manager (and telling them I’d prefer not to share with HR etc) but I worry they’d be required to pass it on regardless. Would any HR workers or managers be able to shed light on this?

Is there a reason you don't want it disclosed? You can have it on record and ask for it not to be disclosed to colleagues.

Quite ridiculous but I know someone who works in HR (outside of work), I really wouldn’t want them knowing

(I know people will say they’re not allowed to breach confidentiality bla bla bla

You can mention it informally off the record but it’s recommended to make it known because a) If you’re treated unfairly under the Disability Act you could lose a claim for financial compensation/recompense
b) won’t get any extra support you need for the role and c) If they think you needed an OT report and didn’t have the chance to prepare one to give you the best chance for the role, this may be an issue in the long run.

You need to weigh up what you’d prefer.