Abstract: A pump for fluid, comprising a pump body defining a bore, a pumping plunger having an end region which is slidably received within the bore, a spill port defined by the pump body in a wall of the bore which port is coverable by the end region of the pumping plunger as the plunger is driven on a pumping stroke, in use, so as to initiate fluid pressurization within a pumping chamber; and a spill feature defined by the pumping plunger being arranged to uncover the spill port during a pumping stroke so as to cause depressurization of the pumping chamber. The pumping plunger further defines a speed sensitive feature configured to permit a controlled leak of fluid from the pumping chamber to the spill port towards the end of a pumping stoke. The invention also encompasses a pumping plunger particularly suited for use in the above described pump.