The invention generally provides a fluid delivery system comprising: a reservoir (7)； a pumping chamber (8) having a volume, an inlet valve (48), an outlet valve (49) and a membrane (47)； an actuator (20)； and a drive member (21). The inlet valve and the outlet valve each comprise a passive normally closed one-way check valve. The inlet valve provides selective fluid communication between the pumping chamber volume and the reservoir. Fluid in the reservoir is at substantially ambient pressure. The drive member is operatively coupled to the pumping chamber membrane. Energising the actuator moves the drive member in reciprocating motion and thereby displaces the membrane to change the pumping chamber volume between a minimum volume and a maximum volume. The pumping chamber volume is held at a pressure above the ambient pressure in the reservoir when the actuator is at rest.
