Most people only receive sick pay under quite limited terms and I know of staff who have been booted while suffering horrible health situations (including cancer).
But I've recently learned that some people, if they have line manager support, will get full pay for many years (three in the case of the person I'm thinking about). I wouldn't mind if this were for genuinely horrible situations but genuinely horrible situations are being sidelined as any NHS worker knows. The person I'm thinking of has a diagnosis of anxiety and adult ADHD.
Their union is now supporting them to seek ill health retirement and I reckon they'll get it.
Things are unfair so never take no for an answer because if you do some other fucker will help themselves.