It depends on the illness being claimed for and how much medical information that is there or whether you are awaiting further medical results. Typically, if all of the information is available and it's very straightforward, you are looking at probably four to six weeks. However, it may take a couple of months depending on medical information required.
In the event that you get diagnosed with a Critical Illness i.e heart attack, cancer, stroke. And that your claim is successful, a lump sum pay out is made to you. So it allows you to pay off any short term debt, pay for day to day living expenses without having to worry about money as you are on the road to recovery.