An excess is a payment that your insurance company will ask you to pay towards any claim that you make.
Normally the total sum of your excess will be divided into two parts:
Compulsory excess: This sum is set by your insurer and will often vary upon your age and your driving experience. The type of car that you are insuring will also be a factor in deciding how much you will have to pay towards this.
Voluntary excess: This is set when you take out an insurance policy. The higher the level of your voluntary excess, the lower the cost of your plan. This can be a good way to lower the initial cost of your insurance policy, but it is worth remembering that in the case of an accident, you will have to pay this amount in full.