A fluid pressure control valve for maintaining the fluid pressure supplied to an associated fluid pressure operated device at or as near a selected value as the operating conditions of the associated fluid pressure operated device indicate to be appropriate. The valve comprises a housing incorporating a spindle axially displaceable in a spindle chamber against spring means by the selected pressure, the spring means being arranged to act between the spindle and a movable abutment. The arrangement of the spindle is such that at any given moment the level of fluid pressure supplied to the associated device by the valve is proportional to the spring force exerted on the spindle by the spring means at that moment, this spring force being normally proportional to the selected pressure thus ensuring that the selected pressure is supplied to the associated device. The spring force is also variable in response to movement of the movable abutment, resulting from a change in the operating conditions of the associated device necessitating a change in the pressure applied to the fluid pressure operated device, under the control of valve means, of which the following is a specification.