A drinking vessel comprises a generally cylindrical container (10) for containing liquid, and a lid (20). The lid comprises a generally cylindrical inner member (21) and a generally cylindrical sealing element (30) which surrounds the inner member (21). The container 10 further comprises a rim (14) and an inner circumferential sealing surface (15). The lid (20) is fixedly insertable into the container 10 in order, when the lid (20) is inserted, to cause the sealing element (30) to lie against the sealing surface so as normally to form a seal with the sealing surface (15). The seal is deformable by suction at the rim (14) such that under the action of the suction liquid within the container (10) is caused to flow from a chamber (13) inside the container out past the rim (14).