A shunt valve assembly comprising: a housing, an exterior of the housing being formed of a physiologically compatible material; a rotor casing (305, 359) disposed within the housing, the rotor casing including a plurality of rotor teeth; an inlet port positioned between the rotor casing and the exterior of the housing, the inlet port terminating at its rotor casing end in a valve seat (103, 4203); a valve element (101, 4205), preferably a spherical valve element, the valve element and the valve seat together forming an aperture; a magnetic rotor (300, 350) disposed within the housing and including a first and second rotor teeth (301, 355; 303, 357) that are configured to alternately engage the rotor casing teeth responsive to an external magnetic field, thereby causing relative rotation between the magnetic rotor and the rotor casing and producing a selected pressure setting of the shunt valve assembly; an outlet port positioned between the rotor casing and the exterior of the housing, the shunt valve assembly configured such that the aperture opens when a pressure of the fluid in the inlet port exceeds the selected pressure setting of the shunt valve assembly so as to vent fluid through the aperture into the outlet port; and characterised by a cantilever spring including a cantilevered arm and a second arm extending substantially parallel to one another and in a same direction from a fixed point of attachment of the spring, wherein the valve element is biased against the valve seat by the spring, and the cantilevered arm of the spring having a free end that rests against the valve element; a check valve coupled to the outlet port, the check valve having a check pressure setting that is lower than the selected pressure setting of the valve assembly. a housing, an exterior of the housing being formed of a physiologically compatible material; a rotor casing (305, 359) disposed within the housing, the rotor casing including a plurality of rotor teeth; an inlet port positioned between the rotor casing and the exterior of the housing, the inlet port terminating at its rotor casing end in a valve seat (103, 4203); a valve element (101, 4205), preferably a spherical valve element, the valve element and the valve seat together forming an aperture; a magnetic rotor (300, 350) disposed within the housing and including a first and second rotor teeth (301, 355; 303, 357) that are configured to alternately engage the rotor casing teeth responsive to an external magnetic field, thereby causing relative rotation between the magnetic rotor and the rotor casing and producing a selected pressure setting of the shunt valve assembly; an outlet port positioned between the rotor casing and the exterior of the housing, the shunt valve assembly configured such that the aperture opens when a pressure of the fluid in the inlet port exceeds the selected pressure setting of the shunt valve assembly so as to vent fluid through the aperture into the outlet port; and characterised by a cantilever spring including a cantilevered arm and a second arm extending substantially parallel to one another and in a same direction from a fixed point of attachment of the spring, wherein the valve element is biased against the valve seat by the spring, and the cantilevered arm of the spring having a free end that rests against the valve element; a check valve coupled to the outlet port, the check valve having a check pressure setting that is lower than the selected pressure setting of the valve assembly.