A liquid storage system comprising: an outer tank for containing a liquid, said outer tank enclosing a liquid storage space; an inner tank (18a, 18b) located within the outer tank and enclosing the liquid storage space; and spacing means (20a, 20b) associated with the outer tank and the inner tank (18a, 18b) for maintaining said tanks in a spaced apart relationship; wherein the spacing means (20a, 20b) are deformable such that, on application of a force to the inner tank (18a, 18b), at least part of the inner tank (18a, 18b) moves relative to the outer tank, characterised in that: the inner tank (18a, 18b) comprises: a first portion comprising a first base wall and first side walls extending from the first base wall, the first side walls surrounding a first opening opposite to the first base wall; and a second portion comprising a second base wall and second side walls extending from the second base wall, the second side walls surrounding a second opening opposite to the second base wall; and the first portion and the second portion are coupled to the outer tank by respective deformable spacing means (20a, 20b) such that the first and second portions may move independently from each other. an outer tank for containing a liquid, said outer tank enclosing a liquid storage space; an inner tank (18a, 18b) located within the outer tank and enclosing the liquid storage space; and spacing means (20a, 20b) associated with the outer tank and the inner tank (18a, 18b) for maintaining said tanks in a spaced apart relationship; wherein the spacing means (20a, 20b) are deformable such that, on application of a force to the inner tank (18a, 18b), at least part of the inner tank (18a, 18b) moves relative to the outer tank, characterised in that: the inner tank (18a, 18b) comprises: a first portion comprising a first base wall and first side walls extending from the first base wall, the first side walls surrounding a first opening opposite to the first base wall; and a second portion comprising a second base wall and second side walls extending from the second base wall, the second side walls surrounding a second opening opposite to the second base wall; and the first portion and the second portion are coupled to the outer tank by respective deformable spacing means (20a, 20b) such that the first and second portions may move independently from each other. the inner tank (18a, 18b) comprises: a first portion comprising a first base wall and first side walls extending from the first base wall, the first side walls surrounding a first opening opposite to the first base wall; and a second portion comprising a second base wall and second side walls extending from the second base wall, the second side walls surrounding a second opening opposite to the second base wall; and a first portion comprising a first base wall and first side walls extending from the first base wall, the first side walls surrounding a first opening opposite to the first base wall; and a second portion comprising a second base wall and second side walls extending from the second base wall, the second side walls surrounding a second opening opposite to the second base wall; and the first portion and the second portion are coupled to the outer tank by respective deformable spacing means (20a, 20b) such that the first and second portions may move independently from each other.