A liquid storage system comprising: a tank for containing a liquid, the tank enclosing a liquid storage space; and a tank liner fixedly attached to an internal surface of the tank (16). The tank liner comprises: a plurality of elements, each element having a hardness value of 2 GPa or above; and a binder material in which the plurality of elements are embedded. The elements have a higher hardness value than the binder material. A distance between a first element and the internal surface of the tank in a direction normal to the internal surface of the tank is different to a distance between a second element and the internal surface of the tank in the direction normal to the internal surface of the tank, the first element being different to the second element.

A method of forming a self-sealing fuel tank includes: providing a container including internal surfaces and external surfaces and configured to hold a fuel; forming a latex coating layer over at least a portion of the internal surfaces and/or external surfaces; depositing or encapsulating an environmental layer over at least a portion of the latex coating layer; where the latex coating layer swells when contacted with the fuel; and where the latex coating layer is formed from a latex coating composition that is substantially free of a non-ionic associative thickener.