Fuel injection system

A fuel injection system comprising an accumulator volume ( 10 ) arranged to be charged with fuel by means of a high pressure fuel pump ( 12 ) and for supplying fuel at a first injectable pressure level to a plurality of fuel injectors ( 22 ), wherein each injector ( 22 ) includes a delivery passage ( 16, 20 ), a valve needle ( 30 ), which is engageable with a seating to control fuel injection, and a control valve ( 26 ) for controlling fuel pressure within a control chamber ( 28 ) so as to control movement of the valve needle ( 30 ). The control valve ( 26 ) has a first operating position in which the control chamber ( 28 ) communicates with a low pressure drain and communication between the control chamber ( 28 ) and the delivery passage ( 16, 20 ) is prevented and a second operating position in which the control chamber ( 28 ) communicates with the delivery passage ( 16, 20 ) and communication between the control.