disclosed is a liquid storage system having an outer tank for containing a liquid , the outer tank enclosing a liquid storage space ; an inner tank located within the outer tank and enclosing the liquid storage space ; and at least one coupling element associated with the outer tank and the inner tank for maintaining the tanks in a spaced apart relationship ; wherein the coupling element is / are deformable such that , on application of a force to the inner tank , at least part of the inner tank moves relative to the outer tank .