A control system controlling the line pressure in a blood supply system in which a first pump 14 is provided to pump blood from a reservoir 10 via a primary passage 18 at a flow rate and at a driving pressure toward a plurality of outlets 26,26a,30, wherein one or more of the outlets are openable to permit flow through the outlet and closable to block flow through the outlet, wherein the control system comprises a monitoring arrangement 22 to determine a pressure value representative of a line pressure in the primary passage 18, and a controller responsive to the monitoring arrangement, the controller configured to control the first pump 14 to maintain the line pressure in the primary passage 18 above a pre-set level.
