There is provided a valve (2, 102, 302, 402) which comprises a housing (4, 04, 204, 304, 404) in which a movable valve element (6, 106, 206, 306, 406) having first and second valve members (14a, 14b; 114a, 114b; 214a, 214b; 314a, 314b; 414a, 414b) is disposed. A plurality of ports (A-E) are disposed in the housing, and first and second seal portions (8a, 8b; 10a, 10b; 108a, 108b; 110a, 110b; 208a, 208b; 210a, 210b; 308a, 308b; 310a, 310b; 408a, 408b; 410a, 410b) are connected to the housing. The first and second seal portions each have a sealed configuration in which first and second pairs of ports are sealed from one another with the first and second valve members respectively. At least one of the first seal portion and the first valve member is deformable such that, when only the first seal portion is in the sealed configuration with the first valve member, deformation allows the second seal portion to be brought into the sealed configuration with the second valve member, and / or at least one the second seal portion and the second valve member is deformable such that, when only the second seal portion is in the sealed configuration with the second valve member, deformation allows the first seal portion to be brought into the sealed configuration with the first valve member.