Fuel injector

A fuel injector 20 for use in an i.c. engine, eg a compression ignition engine, includes an injection valve member 28 having a control surface 48 or control surface associated therewith exposed to fluid pressure in a control chamber 40; a leaf spring element 102 extends transversely through the control chamber 40 to apply a biasing force to the control surface of the injection valve member 28. The biasing force may be applied to the centre of the control surface in line with the longitudinal axis of the valve member 28. The leaf spring 102 may be defined by a U-shaped cut-out feature 114 of a spring plate member 112 positioned between a valve guide body 44 and a control valve body (46, fig.2). The leaf spring element may engage an anti-spin feature (110, fig.4) eg a slot or groove in the valve member 28.