A surgical instrument comprises a housing (1), and a shaft (2) including a proximal end, a deflectable portion and a distal tip (3). A handle (5) is movable between a first position and a second position on the housing, and an actuator (7) is movably coupled to the handle (5) such that movement of the handle between its first and second position causes a corresponding movement of the actuator between a first and a second position in the housing. A deflection wire (10) includes a proximal portion and a distal portion, the distal portion being fixed to the shaft (2), and the proximal portion being affixed to the housing (1) so as to provide a path length for the deflection wire within the housing. The movement of the handle (5) causes the actuator (7) to move to its second position, the second position of the actuator causing an increase in the path length for the deflection wire (10) so as cause a deflection of the distal tip (3) of the shaft.
