Individual income protection insurance is designed to pay out whatever the reason for your being unable to work. There will be a few exclusions, compared to Critical Illness Cover, which only pays out if you contract one of a list of specified illnesses
It pays out for the period that you are unable to work.
Some policies also offer a lump sum payment if you are diagnosed as unable to work.
It will almost certainly exclude unemployment and redundancy.
It will stop payment when you reach retirement age
There is no investment element and no pay out at the end of the policy.
There are all sorts of different policies with small variations that could mean the difference between being able to claim in full and getting a reduced payout, or even nothing.
Deferred periods, i.e. the time between when you stop working and when you can claim for, vary. Sometimes you get a range of choices. Typically they offer 30, 60 or 90 days. Some offer 6 months, 12 months or even 18 months.