A clamp valve is made which comprises a hollow member open at one end and which has a pair of apertures through side walls thereof. A slide is movable in the hollow member and has a transverse aperture therethrough so that a conduit which has a pliable resilient wall can in use be passed through both of the apertures in the hollow member and the aperture in the slide. Biassing means are provided to bias the slide relative to the hollow member so that the conduit is in use normally clamped between an edge of the aperture in the slide and an edge of one of the apertures in the hollow member so that the conduit is normally closed to fluid flow.
