What is income protection?
Income protection pays a regular replacement income, usually tax free, if illness or injury stops you working. Payments begin after a chosen waiting period and can continue until you recover, retire, or the policy term ends.
The definition of incapacity is the thing to check. Own occupation pays if you cannot do your own job; any occupation pays only if you cannot do any job you are suited to, and is much harder to claim on.
The deferred period should line up with employer sick pay and savings — a longer wait cuts the premium substantially. Short-term policies cap payments at one or two years and cost less; full-term policies run to retirement and are what the cover is really for.
It protects the thing every other financial plan depends on: earnings. It is also the least-bought of the main protection products, largely because it is harder to explain than a lump sum on death.