A surgical instrument having a handle 20, elongate shaft, end effector and a rotatable thumbwheel 28 located towards the rear of the handle 20. Rotation of the thumbwheel 28 causes corresponding rotation of the elongate shaft. A handswitch 27 is located on the handle directly above the thumbwheel 28, and operation of this switch 26 controls power supply to electrodes located on the end effector. A moveable grip 22 is located below the thumbwheel 28 and controls clamping movement of the jaw members. A trigger 24 controls deployment of a retractable blade.