Life insurance isn't compulsory when you remortgage, but could be important if your have dependents such as a young family who would not be able to cope with your mortgage if you were to die. If this is the case, you could consider 'term insurance' which is a form of mortgage protection.
This type of life insurance will pay off your mortgage in the event of your death and would certainly give you some peace of mind that your dependents would be able to keep a roof over their heads. You could also 'critical illness cover' which can be added on to your life insurance policy.