Abstract: A fluid flow control valve comprises a plurality of vortex, fluid pressure reduction chambers 1, each vortex chamber having an inlet in the form of a curved flowpath 2 having an inlet orifice 3 of defined cross sectional area which decreases along the length of the inlet flowpath to a minimum point at a throat 4 close to which it opens into the vortex chamber 1. The fluid flow within the vortex chamber takes a generally spiral flow path having both radial and axial components from the throat 4 towards an outlet 5 positioned substantially axially at an end of the vortex chamber, the curvature of the inlet flowpath being such that the direction of the flow therein is in substantially the same direction as the radial component of the flow within the vortex chamber.