A stable flowable aqueous composition comprising at least two component surfactants, each component surfactant having a maximum solubility in water at which a saturated solution forms, wherein the total concentration of all surfactants present in the composition is greater than would be obtained by combining equivalent amounts of saturated solutions of the component surfactants； wherein at least one component surfactant includes a compound of formula (I): wherein R1 represents a C4-36 alkyl group； each of R2, R3, R4 and R5 independently represents a hydrogen atom or a C1-4 alkyl group and wherein at least one of R2, R3, R4 and R5 is not hydrogen and M− represents a cation.
