What you want is an income protection policy or PHI (Pemanent Health Insurance - not to be confused with Health Insurance). This type of policy will cover you for up to a maximum of 3/4 of your salary if you are out of work due to any accident or sickness. It will cover you until you return to work or retire (or chosen retirement age when taking out policy).
In terms of price there are quite a number of factors that come into it. The price is determined by: your age, your occupation, smoker status, the amount of cover you require, and the age you require cover to - usually your expected retirement date.There is also whats know as a deferred period which is the period of time you would need to be out of work for before you can claim on the policy. This is usually 13, 26 or 52 weeks and the price changes depending on which you choose. 13 weeks is the most expensive and it goes down the longer the deferred period.
There are also some occupations which you cannot get cover for so that may also be a problem. If you wish to provide more details I may be able to get you a rough price on it. You may not want to give your salary so if you give the other details I'll have a look.