A rateable proprtion clause means the insured will only be liable for part of the loss where more than one policy is covering the same loss. This is designed to cover the insurer if they pay the whole claim and then are prevented from recovering from the other insurers.

A case where this occurred was Bovis Construction & Another V Commercial Union (2001).

An Insurance policy may have a non contribution clause that states that the insurer will be liable if there is another policy in force covering the same loss. This is to prevent fraud and for policyholders to use insurance as a means of wagering.

at the same time, the insured cannot be left without cover as shown in the case Of Gale V Motor Union Insurance Co. (1928)...